Floyd Mayweather stops Conor McGregor in 10th round of megafight

For awhile there, it looked like Conor McGregor was going to pull off an upset for the ages.

The UFC lightweight champion, making his professional boxing debut in a mega-fight against one of the greatest pugilists of all-time, won the first three rounds of his 154-pound bout against Floyd Mayweather Jr. at T-Mobile Arena in Las Vegas on Saturday night.

But the 40-year-old Mayweather, an undefeated former champion in five weight classes, is known to start slow and pick up the pace as he goes. And that’s exactly what he did, as he turned it up in the middle and finished the bout via TKO in the 10th round.

The time of the stoppage was 1:05 as Mayweather ran his record to 50-0, topping the 49-0 mark set by legendary heavyweight champion Rocky Marciano.

"A win is a win, no matter how you get it,” Mayweather said. “Rocky Marciano is a legend and I look forward to going into the Hall of Fame one day. This was my last fight tonight. For sure. Tonight was my last fight. Tonight I chose the right dance partner to dance with. Conor you are a hell of a champion."

McGregor caught Mayweather’s attention early by cracking him with a sharp left uppercut in the opening round. McGregor attacked Mayweather from odd angles and did his best to muddy the waters, frequently engaging in the clinch and getting away with as many gray-area punches as he could before referee Robert Byrd could intervene.

This went on for the first three rounds, but Mayweather, who was fighting for the first time since retiring in May, 2015, started to up the volume of his punches in the fourth. Mayweather found a home frequently with big right hands. McGregor slowly began to wear down as the rounds wore on.

McGregor, who was derided as a joke by boxing purists in the buildup to the fight, earned plaudits for his heart in the fight, and pushed through to another solid round in the eighth. But Mayweather turned it up in the tenth, raining punch after punch down upon McGregor until Byrd waved the fight off.

"I thought it was close though and I thought it was a bit of an early stoppage,” McGregor said. “I was just a little fatigued. He was just a lot more composed with his shots. I have to give it to him, that's what 50 pro fights will do for you.”

It was the first TKO loss of McGregor’s combat sports career. He’s 21-3 in MMA, but all three losses have been by way of submission.

McGregor never left his feet before the bout was waved off, and claimed that he could have gone on had the fight not been stopped, saying he could push through fatigue.

"I've been strangled on live TV and came back,” McGregor said. “When you're in here in the squared circle, everything is different. Let the man put me down, that's fatigue, that's not damage.”

While there was no official title on the line, Mayweather earned a diamond-and-gold laden “money belt” commissioned by the World Boxing Council for the winner of the fight.