Manny Pacquiao, unquestionably one of the best boxers of his generation, says his third meeting with Timothy Bradley Jr. on April 9 will be the final fight of his career. If that's the case, then it's time to assess Pacquiao's place in boxing history.

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ESPN asked its panel of boxing experts to rank the top 25 pound-for-pound boxers of the past 25 years. The results will be unveiled over eight days on ESPN.com, Facebook (ESPN Boxing) and Twitter (@ESPNBoxing) and counted down from No. 25 to No. 1, which will be announced on the eve of Pacquiao-Bradley III. Fans can use the hashtag #P4Prank to join the discussion and follow along.

Here are the boxers ranked from No. 25 to No. 16:

Coming Thursday: Nos. 15-11

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25. Terry Norris

Record: 47-9, 31 KOs | Years active: 1986-98

Weight classes: Junior middleweight

Titles: 4

Top 3 signature wins: John Mugabi, KO1, 1990; Sugar Ray Leonard, UD12, 1991; Meldrick Taylor, TKO4, 1992

Stats & Info: From 1990-97, Norris had three separate reigns as WBC junior middleweight champion and made 16 title defenses.

ESPN's take: A devastating puncher with a shaky chin, the 2005 Hall of Fame inductee was one of the most exciting fighters of his time. He shot to prominence in 1990 with a title-winning, first-round knockout of Mugabi and gained even more fame by retiring aging legend Leonard in 1991. -- Dan Rafael

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24. Gennady Golovkin

Record: 34-0, 31 KOs | Years active: 2006-present

Weight classes: Middleweight

Titles: 2

Top 3 signature wins: Grzegorz Proksa, TKO5, 2012; Curtis Stevens, TKO8, 2013; David Lemieux, TKO8, 2015.

Stats & Info: Golovkin has won 21 consecutive fights by knockout and made 15 consecutive title defenses, both of which are more than any other current champion in boxing.

ESPN's take: A bit early to write GGG's history, but he has the potential to go down as an all-time great middleweight. Golovkin still has a long way to go and a possible match with Canelo Alvarez might provide more evidence of Golovkin's true abilities. -- Wally Matthews

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23. Winky Wright

Record: 51-6-1, 25 KOs | Years active: 1990-2012

Weight classes: Welterweight, junior middleweight, middleweight

Titles: 4

Top 3 signature wins: Shane Mosley, MD12, 2004; Felix Trinidad, UD12, 2005; Ike Quartey, UD12, 2006

Stats & Info: In his career, Wright won every major version of the junior middleweight title, starting with the WBO version in 1996 and culminating with a 2004 victory over Shane Mosley for the WBC, WBA and lineal titles.

ESPN's take: Wright, whose defensive brilliance was his calling card, spent years fighting in France and England before Mosley gave him a chance to fight him in a 2004 unification fight. Wright responded with a sensational performance to unify three belts and then beat him again in the immediate rematch. -- Dan Rafael

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22. Naseem Hamed

Record: 36-1, 31 KOs | Years active: 1992-2002

Weight classes: Bantamweight, junior featherweight, featherweight

Titles: 3

Top 3 signature wins: Tom Johnson, TKO8, 1997; Kevin Kelley, KO4, 1997; Wilfredo Vazquez, TKO7, 1998

Stats & Info: Hamed made 15 defenses of his WBO featherweight title from 1995-2000, the third most in featherweight division history.

ESPN's take: Hamed's cheeky (some would say arrogant) personality and over-the-top ring entrances helped make him a box-office phenomena, but it was his fighting skills that carried him to the top. He was lightning quick, maddeningly unorthodox and the hardest-hitting featherweight of his era. -- Nigel Collins

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21. Miguel Cotto

Record: 40-5, 33 KOs | Years active: 2001-present

Weight classes: Junior welterweight, welterweight, junior middleweight, middleweight

Titles: 5

Top 3 signature wins: Shane Mosley, UD12, 2007; Antonio Margarito, TKO9, 2011; Sergio Martinez, TKO10, 2014

Stats & Info: Cotto is the only Puerto Rican fighter in history to win world titles in four different weight classes.

ESPN's take: One of Puerto Rico's greatest fighters, the enormously popular Cotto became the island's first four-division titleholder when he stopped Sergio Martinez in the 10th round for the middleweight title in 2014. But no victory was more satisfying for Cotto than stopping Antonio Margarito in their animosity-filled 2011 rematch. -- Dan Rafael

AP Photo/Toru Takahashi

20. Roman Gonzalez

Record: 44-0, 38 KOs | Years active: 2005-present

Weight classes: Strawweight, junior flyweight, flyweight

Titles: 3

Top 3 signature wins: Juan Francisco Estrada, UD12, 2012; Akira Yaegashi, TKO9, 2014; Brian Viloria, TKO9, 2015

Stats & Info: Gonzalez is one of two fighters from Nicaragua to win world titles in three different weight classes, joining Hall of Famer Alexis Arguello.

ESPN's take: A native of Nicaragua, "Chocolatito" has followed in the footsteps of late countryman and mentor Alexis Arguello as a feared puncher. The three-division champion is also among the most well-rounded and complete fighters in boxing today, with an almost artistic beauty to the way he attacks. -- Brian Campbell

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19. Wladimir Klitschko

Record: 64-4, 53 KOs | Years active: 1996-Present

Weight classes: Heavyweight

Titles: 4

Top 3 signature wins: Sam Peter, UD12, 2005; Chris Byrd, TKO7, 2006; David Haye, UD12, 2011

Stats & Info: Klitschko made 18 heavyweight title defenses from 2006-2015, the third most in heavyweight history.

ESPN's take: Admittedly, Wladimir has a monotonous style. But there's no getting around the fact that he owned the sport's premier division from 2005 until 2015 and made 17 successful title defenses. Yes, the rest of the field was ordinary at best, but you don't last that long unless you're damned good. -- Nigel Collins

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18. Erik Morales

Record: 52-9, 36 KOs | Years active: 1993-2012

Weight classes: Junior featherweight, featherweight, junior lightweight, junior welterweight

Titles: 6

Top 3 signature wins: Daniel Zaragoza, TKO11, 1997; Marco Antonio Barrera, SD12, 2000; Manny Pacquiao, UD12, 2005

Stats & Info: Morales won titles in four different weight classes, tied with Juan Manuel Marquez and Jorge Arce for the most among Mexican boxers.

ESPN's take: A warrior, pure and simple. Beat 15 world champions, and his trilogies with Barrera and Pacquiao will be long remembered. Pacquiao eventually proved his superiority, but all three fights with Barrera could have gone either way. -- Wally Matthews

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17. Andre Ward

Record: 29-0, 15 KOs | Years active: 2004-present

Weight classes: Middleweight, super middleweight, light heavyweight

Titles: 2

Top 3 signature wins: Carl Froch, W12, 2011; Mikkel Kessler, TD11, 2009; Chad Dawson, TKO10, 2012

Stats & Info: Ward is one of three American fighters in the past 25 years to win Olympic gold and a world title in boxing (Oscar De La Hoya, David Reid).

ESPN's take: The last American male boxer to win an Olympic gold medal, Ward made a name for himself professionally by winning the Super Six World Boxing Classic in 2011. Ward can do it all in the ring and adjust to any style, although inactivity has stunted his growth in recent years. -- Brian Campbell

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16. James Toney

Record: 76-10-3, 46 KOs | Years active: 1988-present

Weight classes: Middleweight, super middleweight, light heavyweight, cruiserweight, heavyweight

Titles: 3

Top 3 signature wins: Michael Nunn, TKO11, 1991; Vassiliy Jirov, UD12, 2003; Evander Holyfield, TKO9, 2003

Stats & Info: Toney was named the Fighter of the Year by The Ring magazine and the BWAA in 1991 and 2003, joining Evander Holyfield, Floyd Mayweather and Manny Pacquiao as fighters to win the award twice in the past 25 years.

ESPN's take: Toney, with one of the best chins in history, made his name when he scored a dramatic 11th-round comeback knockout of Michael Nunn to win a middleweight title in 1991. For a time in the 1990s, many considered him the No. 1 pound-for-pound fighter. Later, he failed two drug tests, including one that cost him a heavyweight title. -- Dan Rafael