The 6-foot-6 southpaw overwhelmed Thurman with his high volume of punches, bloodied and stopped the former unified welterweight champion in the sixth round of the main event of a Premier Boxing Champions pay-per-view card at MGM Grand Garden Arena. Referee Thomas Taylor mercifully prevented Thurman from taking a worse beating and stopped their 154-pound title fight at 1:17 of the sixth, with Thurman still on his feet.

Thurman (31-2, 23 KOs, 1 NC) bled badly from a cut beneath his left eye. He couldn’t mount much offense against the much taller, younger Fundora, either, and he wasn’t the least bit competitive in a fight Fundora was listed as a 4-1 favorite to win.

Fundora led comfortably on the cards of judges Tim Cheatham (49-46), Max De Luca (50-45) and Steve Weisfeld (50-45) entering the sixth round.

“He’s a great fighter,” Fundora told Jim Gray in the ring after retaining his WBC junior middleweight title. “I think he’s a first-ballot Hall-of-Famer for sure. All respect to Keith. That’s why I had to train so hard and work so hard to prove to him and prove to the world that I’m the best junior middleweight.”

Fundora (24-1-1, 16 KOs), of Coachella, California, is The Ring’s second-ranked contender for an unclaimed 154-pound championship. The 28-year-old champion made his third defense of a WBC belt he won when defeating Tim Tszyu by split decision in a 12-round bloodbath in March 2024 at MGM Grand Garden Arena.

Thurman, meanwhile, disagreed with Taylor’s decision to stop their fight.

“The fight was getting really good,” Thurman said. “The fans were loving the action and the referee stopped the fight too early. They don’t have the guts to let the fights go on like the Erik Morales days. He talked to me and said if I was moving my feet he wouldn’t stop the fight. I wasn’t on the ropes taking shots. It was very unfortunate to not give the fans a better show. Win, lose, or draw, I thought it was a little bit premature. I had more in me.”

Thurman, 37, fought for just the third time since he lost the WBA welterweight title to Manny Pacquiao by split decision in July 2019 at MGM Grand Garden Arena. Injuries to him and his opponents, the COVID-19 pandemic and other factors limited the Clearwater, Florida native’s activity over the past 6½ years, but he jumped at the opportunity to face Fundora, who stands almost a foot taller than him and is nine years younger.

Fundora and Thurman were initially scheduled to fight October 25, but Fundora suffered a hand injury that caused a postponement. It turned out to not be worth the wait, as Fundora toyed with Thurman.

Fundora battered Thurman with power punches during the sixth round. With blood flowing from a cut beneath his left eye, it seemed only a matter of time before Fundora would’ve finished him in a more decisive fashion.

Fundora hurt Thurman with a left hand late that knocked him into the ropes late in the fifth round.

Fundora’s flurry of punches made Thurman cover up in the middle minute of the fifth. Thurman’s right connected barely 10 seconds into the fifth, but he otherwise missed wildly with rights.

Fundora landed left uppercuts in the fourth round as Thurman tried to keep away from him. Thurman couldn’t mount much offense at that point.

Thurman slipped several of Fundora’s punches in the third round, but he couldn’t connect when he was able to work his way inside.

Fundora’s straight left sent Thurman into a squatting position with just over 2:10 to go in the second round.

A left uppercut by Fundora landed toward the end of the first round. Fundora’s straight left backed up Thurman less than 10 seconds into their bout.

Five rounds later, Thurman was left with the first knockout defeat of his 18-year pro career.

“It was a lot of fun,” Thurman said. “Sebastian definitely came in shape. He throws a lot of punches. The uppercut that caught me and cut me was an awkward punch that I’ve never been hit with before. The man brings it. He’s a tremendous champion, and I can lift my head up high knowing I was defeated by a great young fighter.”