Dan Rafael breaks down the fantastic fight between Anthony Joshua and Wladimir Klitschko and what it means for the state of the heavyweight division (0:58)

LONDON -- Anthony Joshua defeated Wladimir Klitschko by TKO in the 11th round Saturday night to retain his heavyweight title and add a vacant belt at a packed Wembley Stadium in London. Here are a few things we learned from the fight.

Joshua is fast becoming boxing's No. 1 star.

Wembley Stadium calls itself the venue of legends, and Joshua's win over Klitschko will go down in history as one of the most memorable sporting occasions at England's national soccer stadium. Joshua's face has been everywhere the past two weeks -- on television, in newspapers and magazines, and on advertising billboards around the city and on the transport network.

Punch stats Punches Joshua Klitschko Landed 107 94 Thrown 355 257 Percent 30% 37% -- Courtesy of CompuBox

After flooring Klitschko three times and then dispatching him in thrilling style in the 11th round, Joshua's profile will only get bigger.

Like unified middleweight world titleholder Gennady Golovkin, Joshua brings guaranteed excitement. He has stopped all 19 of his professional opponents with a record unrivaled in boxing for its ferocity.

But Joshua's appeal is not simply down to his knockout power. His charisma helps him transcend boxing and appeal to mainstream audiences.

Joshua is also raising interest around the world; his clash with Klitschko, the former champion, was shown in over 140 countries.

The fight was screened in the U.S. by rival TV networks Showtime (live) and HBO (same-day tape delay), only the third time in history that has happened.

Heavyweight titleholder Anthony Joshua is becoming one of the biggest stars in boxing. Richard Heathcote/Getty Images

With his good looks and great talent, Joshua has a good chance of being a bigger hit in the States than Klitschko. The Ukrainian failed to shine in appearances on American soil against Bryant Jennings (2015), Sultan Ibragimov (2008) and Lamon Brewster (2004), who stopped Klitschko. Joshua's hopes of making it big Stateside will depend on continuing his knockout form there and appealing to the American public through his personality.

Over in the U.K., Joshua is getting bigger and bigger. He will replace the likes of Andy Murray, David Beckham, Lewis Hamilton and Rory McIlroy as Britain's best-paid sportsman, according to marketing experts. Joshua wants to become a billionaire, and that is not a far-fetched ambition because even more sponsors will be lining up to sign him now.

The attendance of 90,000 was the biggest since 1939 in Britain, and promoter Eddie Hearn was confident the fight would break the U.K. pay-per-view record of 1.15 million buys. Hearn thinks this win makes Joshua the biggest sports star in the U.K., and the biggest star in global boxing.

But to become popular overseas, Joshua has to fight overseas -- which he has yet to do as a professional.

The likes of Manny Pacquiao, Golovkin and Canelo Alvarez are bigger stars globally -- if not in the U.K., where Joshua rules.

But if the Joshua juggernaut continues on its thunderous journey, taking out the likes of Deontay Wilder, Tyson Fury and Joseph Parker, then the British heavyweight will be the new global face of boxing.

At 41, there is still life left in Klitschko

Klitschko might not have won back two of his old world title belts, but he did win back a lot of respect after contributing to a brilliant bout.

The Ukrainian heavyweight ruled for nine and a half years before lacking aggression and ambition in a defeat to Fury in November 2015. Klitschko was also disappointing against Bryant Jennings earlier the same year, and many felt his best days were behind him.

But after a reticent start, a knockdown seemed to shake the former champion into life. Klitschko went down in the fifth, and began swinging wildly when he got back up.

Klitschko was suddenly the aggressor later in the fifth when Joshua became a static target. And in the sixth, Klitschko landed a sledgehammer of a right to the temple to send Joshua down for the first time in his career. Joshua was then in real danger of losing his title. It was evidence that Klitschko still has the power and accuracy to trouble any heavyweight.

Joshua, 27, rediscovered his earlier vim and vigour in the 11th round, and at the time of the stoppage one judge had Klitschko ahead (95-93) while the others scored it for the Briton 96-93, 95-93. Klitschko showed great heart and conditioning to get up from both knockdowns after Joshua landed a series of crushing blows, but how much will his first stoppage loss since Brewster in 2004 take out of him? And will Klitschko push for a rematch?

After beginning his professional career in 1996, Klitschko showed he is still going strong and dangerous at 41.

Joshua has nerves of steel

The Briton has been the most relaxed person in the room at media events the past two weeks, and he showed no sign of losing his nerve on the big stage come fight night. Former champion Evander Holyfield visited Joshua in his changing room before the fight, and on the big screens inside the stadium fans could see how calm he was. Joshua was seen smiling and joking with the American backstage before getting changed and ready for action.

Wladimir Klitschko dropped Anthony Joshua for the first time in his career, but the young Briton recovered to win by TKO. Richard Heathcote/Getty Images

When Joshua walked to the ring, he was still calmness personified as he waved and shook hands with opponents. The early rounds belonged to Joshua, and he was smiling as he employed his jab to good effect.

When he went down for the first time as a professional in the sixth round, Joshua recovered and composed himself before launching another assault which settled the contest in the 11th. He did not panic after being decked, but rode out the round.

Points to work on for Joshua

Joshua looked vulnerable on the ropes, and he appeared to have punched himself out after flooring Klitschko earlier in the fifth round. Joshua continued to be subdued in the sixth before he was caught by a right over the top, and it took a few rounds for the Briton to regain his confidence.

"It is what it is, and I came through and won," said Joshua.

Since he was floored and one judge had Klitschko ahead at the time of the stoppage, it can hardly be deemed a flawless display by Joshua, no matter how impressive the finish was.

"I took a round off to get my breath back, and then I said, you're in a bad place," said Joshua.

"I tried to recover and then step it up in the later rounds, that was the plan.

"I learned I can knock out anyone. Sometimes you have to ride a few shots and take a few shots before pushing on for victory."

But Klitschko said, "I think he is vulnerable and it's maybe something he needs to work on."

Joshua's right uppercut is deadly

Whenever the IBF-WBA titleholder uncorked his right uppercuts, they did damage, and most heavyweights would not have gotten up as Klitschko did. Right uppercuts featured in all three of Joshua's knockdowns of Klitschko, and the punch rescued the champion in many ways.

Klitschko could not avoid the shots and was caught by right uppercuts within moments of each other in the telling 11th. It was Joshua's most potent and important weapon.

Joshua was more aggressive and dynamic than Klitschko and when the champ had his opponent in trouble in the 11th, he did not let him off the hook as he did in the fifth. And when Joshua saw the openings, he unloaded the right uppercuts to great effect.

They may well do it again

This fight set record after record, including earning the fighters upward of £15 million each. With rematch clauses in the contracts, it seems likely they will do it again after producing the most entertaining world heavyweight title fight in recent years.

The latest a rematch could take place at the outdoor Wembley Stadium would be September this year due to the U.K. weather. The Principality Stadium in Cardiff, formerly the Millennium Stadium, has a roof and could be Britain's best bet to stage a rematch later in 2017. It was the venue for Joe Calzaghe's super-middleweight title unification fight against Mikkel Kessler in 2007.

"It's more likely to be at [Principality Stadium] if it's in the U.K., or it might take us to a new territory," said promoter Eddie Hearn.

Staging the rematch in Las Vegas could be an option, which would give Joshua the chance to box in America for the first time.

"I don't mind fighting him again, if he wants the rematch," Joshua said.

Klitschko, however, declined to make any announcement about his future, confirming neither a rematch nor his retirement.

"I'm not going to consider anything. I'm not going to make any statements. I will take my time and let you know," Klitschko said.

"I have a rematch clause in the contract which I can execute. Right now I will not announce anything."