Floyd Mayweather has beaten Irishman Conor McGregor by way of technical knockout in the 10th round of their much-hyped fight to keep his perfect record intact.

The most unusual megafight in years went longer and was more competitive than many expected when an unbeaten, five-division world champion boxer took on a mixed martial artist making his pro boxing debut on Saturday.

Mayweather came out of retirement at 40 for the fight.

While 29 year-old McGregor had the T-Mobile Arena crowd behind his improbable quest, Mayweather survived a rough beginning and gradually took control.

Mayweather thus extended his career unbeaten record to 50, surpassing heavyweight great Rocky Marciano’s 49-0 record for most wins without a loss or draw.

He pummelled McGregor in the 10th, landing numerous shots and chasing his opponent around the ring until referee Robert Byrd saved the Irishman and stopped the fight.

“I think we gave the fans what they wanted to see,” Mayweather said.

McGregor had vowed to knock Mayweather out within two rounds, and he won the early rounds with movement and punches to the head. But the tide of the fight turned in the fourth round.

Floyd Mayweather & Conor McGregor

“Our game plan was to take our time, go to him and take him out in the end,” Mayweather said. “I guaranteed everybody this fight wouldn’t go the distance.”

Afterward, McGregor went over and hugged Mayweather.

He seemed almost happy in the ring afterward, secure that he had given a good performance even in losing.

“I was a little fatigued,” he said. “He was composed in there, that’s what 50 pro fights can give you.”

Mayweather, who came out of retirement for a potential $300m (£230m) pay day said he was not going to fight again.

“This is my last fight for sure. 50-0 sounds good, I’m looking forward to going into the Hall of Fame,” Mayweather said. “I picked the best dance partner to do it with.”