Demetrious Johnson, one of the most dominant champions in mixed martial arts history, suffered a crushing defeat to Adriano Moraes on Wednesday during a landmark night for Asian-based promotion One Championship.

The One Championship event took place in Singapore and was aired live in the U.S. on TNT, marking the company's first live telecast on U.S. television.

Johnson (30-3-1), widely considered to be one of the greatest fighters of all time, was an obvious candidate to headline. As a UFC flyweight champion, he set the record for consecutive title defenses, defending the belt 11 times from 2013 to 2018.

But it was Moraes (19-3) who made the most of the opportunity, knocking Johnson out with a wicked knee strike at 2 minutes, 24 seconds of the second round to retain his flyweight title. The knee would have been illegal under MMA rules in the U.S., as Johnson was in a grounded position when he was hit, but those strikes are allowed under the One Championship banner in Asia.

"I have to go back home and look at the fight, see when I made mistakes," said Johnson, 34, who had never been knocked out before Wednesday. "Adriano is very long, big. It was hard trying to get to him. This is part of the game. You stay in this game long enough, this is bound to happen at some point, right?"

Moraes, of Brazil, had waited years for the opportunity to fight Johnson. Though the fight was for the flyweight title, it was actually fought at 135 pounds, as One Championship's weight classes are modified from those in the U.S. to discourage extreme weight cutting. Moraes first won a title in One Championship in 2014. He lost the belt in 2015, before regaining the undisputed title in 2017.

Moraes' height and reach advantage offered Johnson significant problems early. Although there wasn't much offense in the opening round, it was obvious Johnson was having a hard time corralling his rangy opponent, and he struggled to match Moraes' physicality on the ground. Moraes nearly landed a standing knee in the second round, just moments before a right uppercut dropped Johnson and then the final knee strike put him out cold.

One Championship has several more live events planned on TNT this month, although Wednesday's card offered the best lineup by far in terms of name recognition in the U.S.

Alvarez-Lapicus ends in quick disqualification

In addition to the flyweight main event, One Championship promoted a lightweight bout between former Bellator MMA and UFC champion Eddie Alvarez and the promotion's No. 2-ranked lightweight, Iuri Lapicus. The co-feature had an unfortunate ending, in which Alvarez (30-8) was disqualified in the first round for blows to the back of the head.

Alvarez, of Pennsylvania, scored an early takedown and trapped Lapicus' legs beneath him along the fence. As Alvarez started throwing wide right hands from top position, Lapicus turned his head toward the fence, exposing the back of his head. Alvarez continued to throw shots until Lapicus reacted badly to one of them and fell back toward the canvas.

The action was paused as the referee called an illegal blow and separated the fighters. Alvarez immediately contested the legality of the blows but later expressed only concern for Lapicus' health.

"Iuri was turning his head the other way, and the referee warned me, 'Back of the head!'" Alvarez said. "If you see, I take my head and shove his head towards the side where the punches were coming from. On top of that, I thought as long as I'm hitting the ear, I thought it was legal. Whatever call the referee makes is fine. I hope Iuri is totally fine. This game is so dangerous, all I care about is everybody staying safe."

Had Alvarez won the bout, he would have been a step closer to competing for One's lightweight championship. As is, he suffers his third defeat in four fights.