HBO and boxing have been synonymous for nearly half a century, but that is coming to an end.

The "network of champions," which called itself the "Heart and Soul of Boxing" and "built legends one round at a time" on its iconic "World Championship Boxing" and "Boxing After Dark" series, has thrown in the towel on the sport. It will air the final card of its mostly glorious 45-year boxing history on Saturday (10:20 p.m. ET/PT) after having televised, and proactively helped make, most of the biggest fights in the sport.

The last card will take place at the StubHub Center in Carson, California, and it's a weak "Boxing After Dark" tripleheader that will send the network out with a whimper, not a bang, after 1,119 fights aired since 1973. Undisputed women's welterweight champion Cecilia Braekhus defends against Aleksandra Magdziak-Lopes in the main event, junior bantamweight Juan Francisco Estrada faces Victor Mendez in the co-feature, and unified women's middleweight titlist Claressa Shields fights Femke Hermans in the opener.

That's not exactly the kind of big-time boxing the network was known for during the glory days that are long past.

The great Hall of Fame broadcaster Larry Merchant served as ringside analyst for 34 years, from 1978 to 2012, before retiring. But the 87-year-old still closely follows boxing and will be back at ringside for a brief guest appearance to talk over old times with longtime broadcast partner Jim Lampley. I'm looking forward to hearing Merchant's words of wisdom on the air one more time and watching the network's retrospective on its boxing history far more than the bouts.

When HBO announced in September that it was ending boxing coverage, Merchant summed it up as only he can do.

"Once upon a time we were a promising kid. Then a challenger. Then a champion. A great champion. A longtime champion. And then a has-been who finally retired," Merchant said. "So long, champ."

I have spent most of my life obsessing over HBO boxing. Talking about it. Thinking about it. Writing about it. So as HBO bows out, I present my inexact list of the 45 best/biggest/most memorable/most important fights the network has aired over the past 45 years:

Buster Douglas scored the biggest upset in boxing history when he finished Mike Tyson in 1990. AP Photo/Tsugufumi Matsumoto

1. Buster Douglas KO10 Mike Tyson, Feb. 11, 1990, Tokyo: In the most shocking upset in boxing history, and perhaps all of sports, Douglas did the unthinkable as he ended the aura of Tyson's invincibility. Douglas survived an eighth-round knockdown and knocked Tyson out to win the undisputed heavyweight title in Rocky-like fashion in a terrific and unforgettable fight.

2. Marvin Hagler KO3 Thomas Hearns, April 15, 1985, Las Vegas: In arguably the greatest action fight ever, including the awe-inspiring first round, Hagler retained the middleweight title in a breathtaking and brief slugfest often called the greatest eight minutes in boxing history.

HBO fighter appearances by decade 1970s: Sugar Ray Leonard (3)

1980s: Mike Tyson (13), Marvin Hagler (11)

1990s: Oscar De La Hoya (19), Pernell Whitaker (19), Roy Jones Jr. (18)

2000s: Floyd Mayweather (18), Shane Mosley (18), Wladimir Klitschko (16), Jermain Taylor (16)

2010s: Gennady Golovkin (15), Sergey Kovalev (14), Canelo Alvarez (11), Terence Crawford (11)

3. Riddick Bowe W12 Evander Holyfield I, Nov. 13, 1992; Holyfield W12 Bowe II, Nov. 6, 1993; Bowe TKO8 Holyfield III, Nov. 4, 1995, all Las Vegas: All three fights in this legendary trilogy were rock 'em, sock 'em slugfests with Bowe winning the undisputed heavyweight title in the first fight, losing it in the second one (famously interrupted by "Fan Man") and stopping Holyfield in the rubber match.

4. Manny Pacquiao D12 Juan Manuel Marquez I, May 8, 2004; Pacquiao W12 Marquez II, March 15, 2008; Pacquiao W12 Marquez III, Nov. 12, 2011; Marquez KO6 Pacquiao IV, Dec. 8, 2012, all Las Vegas: The greatest four-fight series in history stretched over eight years and produced one great and competitive fight after another. It began with an epic draw for the featherweight title, included Pacquiao winning the junior lightweight title in the rematch, retaining a welterweight title in the third fight and Marquez rallying for one of the most shocking knockouts ever in the fourth fight.

Aaron Pryor, right, retained his junior welterweight title with a win over Alexis Arguello in one of the greatest fights in history. Ken Regan/Getty Images

5. Aaron Pryor TKO14 Alexis Arguello I, Nov. 12, 1982, Miami: Pryor retained his junior welterweight title and prevented Arguello from becoming the first fighter to win world titles in four divisions in one of the greatest fights in history. They punished each other until Pryor, perhaps energized by whatever infamous trainer Panama Lewis had given him between rounds from the bottle "that I mixed," overwhelmed Arguello with an onslaught until he slumped to the canvas.

6. Erik Morales W12 Marco Antonio Barrera I, Feb. 19, 2000; Barrera W12 Morales II, June 22, 2002; Barrera W12 Morales III, Nov. 27, 2004, all Las Vegas: The bitter Mexican rivals produced one of boxing's greatest trilogies, with Morales edging Barrera in a junior featherweight unification fight in their first epic battle, Barrera ending Morales' featherweight title reign in the rematch and Barrera winning again in a junior lightweight title fight in the rubber match.

Mickey Ward, right, defeated Arturo Gatti in 2002 in the first of three great fights between them. Photo by The Ring Magazine/Getty Images

7. Micky Ward W10 Arturo Gatti I, May 18, 2002, Uncasville, Connecticut; Gatti W10 Ward II, Nov. 23, 2002, Atlantic City, New Jersey; Gatti W10 Ward III, June 7, 2003, Atlantic City: A legendary trilogy by junior welterweight warriors who became close friends by the time it was over and whose names can't be said without the other. They left it all in the ring, with fights I and III each named fight of the year.

8. Sugar Ray Leonard TKO14 Thomas Hearns I, Sept. 16, 1981, Las Vegas: The all-time greats and welterweight champions met for the undisputed title in one of the most anticipated fights ever, and it lived up to the hype, as Leonard mounted a late rally to finally stop the fading Hearns, with trainer Angelo Dundee's famed words from the corner ringing in his ear: "You're blowing it now, son! You're blowing it!"

9. Julio Cesar Chavez TKO12 Meldrick Taylor I, March 17, 1990, Las Vegas: The undefeated junior welterweight champions met to unify titles in a legendary fight that ended with the most controversial stoppage in history and one of the most dramatic comebacks. Taylor was on his way to a decision when Chavez dropped him late in the final round and got the ultimate comeback when Taylor beat the count but referee Richard Steele stopped the fight with two seconds left.

10. Felix Trinidad TKO12 Fernando Vargas, Dec. 2, 2000, Las Vegas: In perhaps the greatest junior middleweight fight ever, Trinidad and Vargas met to unify titles and produced a classic in which Vargas survived two first-round knockdowns, dropped Trinidad in the fourth and eventually got KO'd in the final round.

11. "Prince" Naseem Hamed KO4 Kevin Kelley, Dec. 19, 1997, New York: After signing a fat contract with HBO, featherweight champion Hamed made his American debut in incredibly memorable fashion as he and Kelly waged the Hagler-Hearns of featherweights, combining for six knockdowns.

12. Marco Antonio Barrera KO12 Kennedy McKinney, Feb. 3, 1996, Inglewood, California: The first "Boxing After Dark" main event set the tone for the iconic series, as Barrera retained his junior featherweight title in an unforgettable war in which he suffered an 11th-round knockdown but floored giant-hearted McKinney five times.

13. Shane Mosley W12 Oscar De La Hoya I, June 17, 2000, Los Angeles: The friendly childhood rivals opened Staples Center for boxing in their hometown with a sensational, high-caliber fight that featured a mix of toe-to-toe action and skills, but one Mosley made the necessary adjustments in the second half of the fight to score the mild upset and win the welterweight title.

14. Arturo Gatti KO6 Wilson Rodriguez, March 23, 1996, New York: Gatti was down in the second round and his right eye was closing before he rallied for a sixth-round knockdown, followed by a tremendous knockout to preserve his junior lightweight title in an unforgettable comeback.

15. Sugar Ray Leonard W12 Marvin Hagler, April 6, 1987, Las Vegas: In a result still debated to this day, Leonard came off a three-year layoff to finally face Hagler, moved up in weight and won the middleweight title by controversial split decision in a memorable fight.

16. Gennady Golovkin D12 Canelo Alvarez I, Sept. 16, 2017; Alvarez W12 Golovkin II, Sept. 15, 2018, both Las Vegas: Two terrific fights that featured lots of action and controversial decisions, as GGG retained the middleweight title in the first fight and Canelo won it by the slimmest of margins in the rematch.

Anthony Joshua, right, defeated Wladimir Klitschko in April 2017 in the biggest win of his career so far. Richard Heathcote/Getty Images

17. Anthony Joshua TKO11 Wladimir Klitschko, April 29, 2017, London: All-time great heavyweight championship fight before 90,000 at Wembley Stadium and the 2017 fight of the year in which both fighters were down in a dramatic battle that ended with Joshua retaining his belts and sending Klitschko into retirement.

18. Lennox Lewis TKO6 Vitali Klitschko, June 21, 2003, Los Angeles: Heavyweight champion Lewis and Klitschko were supposed to fight separate fights on an HBO PPV card as a prelude to an eventual showdown. But when Lewis opponent Kirk Johnson dropped out two weeks earlier, they fought each other on HBO and put on a battle for the ages. In an intense brawl, Lewis, in what turned out to be his final fight, was trailing on the scorecards when the fight was stopped because of gruesome cuts around Klitschko's left eye.

19. Evander Holyfield W12 George Foreman, April 19, 1991, Atlantic City: The first main event of the modern pay-per-view era was an outstanding fight between prime undisputed heavyweight champion Holyfield making his first defense against the inspirational Foreman, who was in the midst of a comeback after 10 years in retirement but showing he could still hang with anyone.

20. Manny Pacquiao TKO12 Miguel Cotto, Nov. 14, 2009, Las Vegas: Offensive machine Pacquiao reached the apex of his career as he dropped Cotto twice and stopped him to win a welterweight world title in a terrific fight that gave Pacquiao a title in a record-setting seventh division (which he would later break).

21. Timothy Bradley Jr. W12 Ruslan Provodnikov, March 16, 2013, Carson, California: It wasn't much of a fight on paper, but it turned out to be an epic slugfest and the fight of the year, as Bradley, usually a boxer, threw caution to the wind and engaged all-out brawler Provodnikov in a toe-to-toe slugfest. Bradley, badly hurt in the early rounds and down in the 12th round, hung on to retain his welterweight title.

22. James Toney W12 Vassiliy Jirov, April 26, 2003, Mashantucket, Connecticut: In arguably the greatest cruiserweight fight ever, Toney was told by trainer Freddie Roach he needed a knockdown in the 12th round and he got it to cap the dramatic slugfest in which he won the title, even though it turned out he didn't need the knockdown.

Erik Morales, right, defeated Manny Pacquiao in the first fight of their trilogy in 2005. Donald Miralle/Getty Images

23. Erik Morales W12 Manny Pacquiao I, March 19, 2005; Pacquiao TKO10 Morales II, Jan. 21, 2006, both Las Vegas: They fought three nontitle junior lightweight bouts, but it was the first two incredible slugfests that will be remembered forever.

24. Riddick Bowe W-DQ7 Andrew Golota I, July 11, 1996, New York; Bowe W-DQ9 Golota II, Atlantic City: Golota took it to Bowe in both of these heavyweight battles but couldn't keep from hitting him low and was disqualified twice, the first one setting off an ugly riot inside Madison Square Garden.

25. Antonio Tarver KO2 Roy Jones II, May 15, 2004, Las Vegas: Six months earlier, pound-for-pound king Jones escaped with a majority decision over Tarver in their light heavyweight title fight for which Jones had shed a tremendous amount of weight after beating John Ruiz for a heavyweight title. As they stood at center ring for final instructions, Tarver ruefully asked, "You got any excuses tonight, Roy?" Then he destroyed Jones in a shocking knockout, the first legit loss of Jones' legendary career.

26. Antonio Margarito TKO11 Miguel Cotto, July 28, 2008, Las Vegas; Cotto TKO10 Margarito, Dec. 3, 2011, New York: In a classic Mexico-Puerto Rico rivalry fight, Margarito busted Cotto up and stopped him to win a welterweight title in a great fight, but many suspected he did so with loaded gloves since he was caught trying to fight using illegal mitts in his next bout. So the rematch was as bitter a grudge match as it gets, and Cotto exacted revenge and kept his junior middleweight belt by bashing up Margarito's surgically repaired eye.

27. Lennox Lewis KO8 Mike Tyson, June 8, 2002, Memphis: Boxing's richest fight at the time was the final summit meeting of the 1990s heavyweight era that saw champion Lewis pound out the remnants of Tyson in one of the most anticipated fights in history that represented the first joint PPV between HBO and rival Showtime.

Sergio Martinez, left, scored a terrific KO of Paul Williams in Round 2 of their rematch in 2014. AP Photo/Tim Larsen

28. Paul Williams W12 Sergio Martinez I, Dec. 5, 2009; Martinez KO2 Williams II, Nov. 20, 2010, both Atlantic City: Williams was supposed to challenge Kelly Pavlik for the middleweight title, but when he dropped out, Martinez took what became a nontitle fight and they waged an all-out brawl in which both were down in the first round. After Martinez won the title from Pavlik, he met Williams in a rematch in which Martinez turned out the lights with one of the most sensational KOs ever.

29. Mike Tyson KO1 Michael Spinks, June 27, 1988, Atlantic City: Tyson reached the apex of his career with this memorable 91-second demolition of Spinks to retain the undisputed heavyweight title and become the lineal champion in what was, at the time, the richest fight in history.

30. George Foreman KO10 Michael Moorer, Nov. 5, 1994, Las Vegas: Not a great fight but it had one of the most memorable moments in boxing history as underdog Foreman, who was being toyed with, connected with a right hand on the point of the chin to knock Moorer out and regain the heavyweight title at age 45, making him the oldest heavyweight champion in history -- 20 years after he had lost it to Muhammad Ali in the "Rumble in the Jungle."

31. Hasim Rahman KO5 Lennox Lewis I, April 21, 2001, Brakpan, South Africa: It wasn't quite Douglas-Tyson, but Rahman pulled off a gargantuan upset to win the heavyweight title in the wee hours of the South African morning to accommodate HBO's live prime-time broadcast in the U.S.

32. Juan Manuel Marquez KO9 Juan Diaz I, Feb. 28, 2009, Houston: Marquez retained the lightweight world title -- and picked up a pair of vacant belts -- in Diaz's hometown in a bloody back-and-forth battle that was the fight of the year. It ended with Marquez dropping Diaz in the ninth round and then flattening him moments later.

Hall of Fame referee Steve Smoger stopped the fight in Round 7 when Kelly Pavlik dropped Jermain Taylor in 2007 to win the middleweight title. Al Bello/Getty Images

33. Kelly Pavlik TKO7 Jermain Taylor I, Sept. 29, 2007, Atlantic City: The middleweight title changed hands in a dramatic thriller in which Pavlik, on the verge of being stopped on a hard knockdown in the second round, was trailing on the scorecards when he unleashed a flurry of brutal shots that separated Taylor from his senses.

34. Miguel Cotto KO7 Ricardo Torres, Sept. 24, 2005, Atlantic City: Cotto, defending his junior welterweight title, engaged in this exceptional slugfest that made him a star, as he walked through fire to eventually score a knockout and make himself must-see TV.

35. Ike Ibeabuchi W12 David Tua, June 7, 1997, Sacramento: Longtime heavyweight contender Tua and rising contender Ibeabuchi slugged it out in a close, grinding battle that tested their outstanding chins to the highest degree as they combined to throw 1,730 punches, a staggering total for heavyweights.

36. Mike Tyson KO2 Trevor Berbick, Nov. 22, 1986, Las Vegas: A new era began as the 20-year-old Tyson ruthlessly became the youngest heavyweight champion after he annihilated Berbick, leaving him flopping around the ring like a fish out of water when he tried to get up from a devastating left hook to the jaw.

37. Marco Antonio Barrera W12 Naseem Hamed, April 7, 2001, Las Vegas: Hamed was the heavy favorite but Barrera, typically a brawler, turned boxer and stunningly -- and easily -- outpointed Hamed to win the featherweight title in a career-defining victory.

Bernard Hopkins, left, became the undisputed middleweight champion with a TKO in Round 12 over Felix Trinidad days after the terrorist attacks in New York City in 2001. Al Bello /Getty Images

38. Bernard Hopkins TKO12 Felix Trinidad, Sept. 20, 2001, New York: In the sadness of New York two weeks post-9/11, life went on as Hopkins stunningly whipped Trinidad on an emotional night and in a masterful performance to become the undisputed middleweight champion.

39. Larry Holmes TKO13 Gerry Cooney, June 11, 1982, Las Vegas: There was an ugly buildup because of race in a fight that pit the black Holmes in a heavyweight title defense against the so-called "great white hope" Cooney, who showed huge heart but ultimately was stopped in a good fight.

40. Floyd Mayweather TKO10 Ricky Hatton, Dec. 8, 2007, Las Vegas: It was an entertaining fight between the undefeated welterweight champ Mayweather and undefeated junior welterweight champ Hatton moving up in weight, but what made it special was the unparalleled atmosphere as some 30,000 Brits came to town to root for Hatton.

41. Johnny Tapia W12 Danny Romero, July 18, 1997, Las Vegas: In the biggest junior bantamweight fight ever, the bitter Albuquerque, New Mexico, rivals met to unify titles, and it was the older Tapia, with a masterful boxing display, who turned back a stiff challenge from the younger, bigger puncher Romero.

42. Pernell Whitaker TKO11 Diobelys Hurtado, Jan. 24, 1997, Atlantic City: Whitaker, the pound-for-pound great, was being taken to school by the unknown Hurtado in what was supposed to be a tuneup for a mega fight with Oscar De La Hoya. Whitaker was down on all three scorecards, and the fight with De La Hoya, who was ringside, was slipping away when he rallied from nowhere to score a brutal knockout to retain the welterweight title.

43. Floyd Mayweather W12 Oscar De La Hoya, May 5, 2007, Las Vegas: Mayweather moved up and took De La Hoya's junior middleweight title in a competitive fight that may have lacked for action but provided an incredible buildup that included the birth of HBO's landmark "24/7" series.

44. Felix Trinidad W12 Oscar De La Hoya, Sept. 18, 1999, Las Vegas: The undefeated welterweight champions met in their prime in what was the richest non-heavyweight fight in history at the time. It failed to deliver the expected action but, oh, did it deliver controversy with De La Hoya appearing to dominate most of the fight only to be robbed of the decision despite his easing up in the final three rounds.

45. Floyd Mayweather W12 Manny Pacquiao, May 2, 2015, Las Vegas: It took five years and agonizing on-and-off negotiations for the two best fighters of their era to finally meet in what was by far the richest fight in boxing history and a joint fight with rival Showtime. Mayweather won handily to unify welterweight titles, but the fight itself was forgettable.

Note: Although HBO televised Ali-Joe Frazier III, Ali-Foreman and Foreman-Frazier I in its early years, the network did not produce the telecast and was not the primary broadcaster, so I elected not to include them because they are not considered true "HBO fights."