Conor McGregor's six-fight UFC winning streak has continued with a stunning second round TKO of Chad Mendes at the MGM Grand Arena.

The Irish featherweight was cut in the first round and appeared to struggle to deal with his opponent’s power in the clinch, but sensationally recovered to knock Mendes to the ground with a devastating left hand as the second round approached its conclusion.

The American sagged to the floor and covered his head as McGregor pounced to deal out further punishment. Mendes could no longer defend himself, and the referee stopped the fight.

It was an incredible turnaround, given that until just a few seconds before the decisive exchange, the fight had been slipping out of McGregor’s control.

Mendes had taunted the Irishman for dropping too much weight and looking scrawny, and in the first part of the fight it seemed his words were being borne out.

McGregor was his usual self, taunting Mendes and posturing for the Irish-dominated crowd, while Mendes seemed calm and answered McGregor’s antics with a grin.

McGregor opened the fight with a couple of extravagant spinning kicks, but Mendes quickly grabbed his ankle and bundled him onto his back. McGregor quickly escaped this first Mendes grapple and taunted his opponent, but it was an ominous sign early in the fight.

McGregor kept on the front foot, sneering and leering to provoke Mendes, but the American was waiting for opportunities to barrel forward, grab him around the waist and take him to the ground.

In the second half of the first round he did so spectacularly, picking McGregor up bodily and slamming him to the ground. He brought his left forearm savagely down on McGregor’s head, opening up McGregor’s left eyebrow.

It was the first time the Irishman had been cut in the UFC. It looked as though he was struggling to deal with the shorter, thickly-built Mendes’ strength, and the end of the first round came as a relief.

The second round brought more of the same, at least at first. Mendes took McGregor to the floor again and there followed a heartstopping sequence in which it looked as though McGregor’s hype train was about to go careering horribly off the rails.

The two fighters were locked together, McGregor on his back, Mendes on top of him with his head buried just below McGregor’s chin, McGregor’s legs locked around Mendes waist, trying to keep his opponent at bay.

Mendes was trying to methodically work his way up McGregor’s body to create the time and space to lift up and slam down on McGregor’s head with brutal chopping forearms.

It seemed as though Mendes had only to keep this up and he would inevitably, as he had promised, punch a hole through McGregor’s face.

At another point it seemed as though Mendes might have got a grip around McGregor’s neck for a possible submission.

But McGregor clung on, showing supreme resilience and resourcefulness to wriggle out of the death grip with roughly a minute left in the round. Suddenly the fighters were back on their feet, back to the way McGregor wanted it, and the crowd could see that the effort had taken its toll on Mendes, who was clearly puffing.

It looked as though McGregor had earned a reprieve and the chance to take the fight into a third round. Instead, he attacked, and amazingly smashed his way through Mendes’ defences.

The first punch grazed Mendes but the second, an overhand left that passed over Mendes’ right shoulder and crunched into the side of his jaw, effectively finished the fight.

The thousands of Irish at the MGM Grand Arena went wild as the clearly emotional McGregor climbed atop the barrier to take their acclaim.

“I’m absolutely blown away by the support, I can’t put into words how grateful I am,” he told the crowd.

“So much went on in the buildup to this. So much media obligations, we had to travel around the world twice. I’ve been hearing all the time that I’m protected from this style of opponent. So they gave me the challenge I was supposed to be protected from, I knew I was going to prove to people that I’m a true fighter.

“I knew I’d get one... I can go all fucking day, Joe [Rogan], I swear to God, all day I can go. The precision of the left hand. Nobody can take that left hand shot, it’s a s simple as that. Everybody breaks. And he broke.

“I also want to say thank you to my team, my family, it’s a tight, tight circle. The Irish people that support me, I swear to God I do this for us.”

For his part, Mendes thanked McGregor for agreeing to fight him at just two weeks’ notice, given that he had been preparing to face a totally different kind of opponent in José Aldo.

“The guy’s tough. He backed up his talk,” Mendes said.

The crowd cheered these magnanimous sentiments, and Mendes looked up at the stands.

“These Irish guys... You guys are crazy. I wish we had so much support like this. It’s unbelievable to see the support you give your athletes.”

Announcer Joe Rogan told McGregor that he was now set for a fight against José Aldo which will be “the biggest in the history of the UFC.”

Once again, with his most complete UFC performance yet, McGregor has delivered.