Kamaru Usman was well on his way to a sixth title defense and a record-tying 16th straight UFC win last summer. He was the undisputed best pound-for-pound fighter on the planet and about one minute away from another accolade that would vault him into a discussion about the greatest fighters of all time.

And then Leon Edwards cracked Usman upside the head with a left kick. Less than 60 seconds from a sure defeat, Edwards pulled a Hail Mary, finishing the dominant champion at UFC 278. It was a stunning comeback, the best knockout of 2022, and it won Edwards the UFC welterweight title. Usman had already beaten Edwards once seven years earlier. But now, with the stakes at their highest, Edwards evened the score.

Edwards and Usman will meet for a third time Saturday in the main event of UFC 286 in London. Edwards' welterweight title -- the one Usman held for more than three years -- will be on the line. ESPN has Usman ranked No. 4 and Edwards ranked No. 7 in its pound-for-pound MMA rankings.

Edwards (20-3, 1 NC) is unbeaten in 11 straight fights. He has not lost since Usman defeated him via unanimous decision in 2015. Edwards, 31, is the first Jamaican-born champion in UFC history and owns wins over Rafael dos Anjos, Nate Diaz, Donald Cerrone and Vicente Luque.

Usman (20-2) last suffered a defeat before the Edwards fight in 2013, just his second career pro bout. The Nigerian-born fighter who trains out of Colorado had two wins apiece over Colby Covington and Jorge Masvidal during his title reign. Usman, 35, beat Tyron Woodley by unanimous decision to win the championship at UFC 235 in March 2019.

In the co-main event Saturday, former interim lightweight champion Justin Gaethje will take on the up-and-coming Rafael Fiziev. Gaethje (23-4), a 34-year-old from Arizona, has won five of his past seven fights, with those two losses coming in bouts for the UFC lightweight belt. Fiziev (12-1), a 30-year-old Kazakh-born fighter competing out of Florida, has won six straight UFC fights.

Also on the card, women's flyweight prospect Casey O'Neill returns from knee surgery to face former title challenger Jennifer Maia, Gunnar Nelson takes on Bryan Barberena in a welterweight bout, and former middleweight title challenger Marvin Vettori meets Roman Dolidze.

Follow along as Brett Okamoto, Marc Raimondi and Jeff Wagenheim recap all the action, or watch the fights on ESPN+ PPV.