The charismatic featherweight from Dublin made his U.S. debut Saturday night in America's most Irish city. A throng of green-clad fans waving Irish flags at TD Garden gave his entrance a rock-star's reception, and he dominated scrappy Max Holloway for 15 minutes before earning a lopsided unanimous-decision victory.
So why was the man who has the potential to become Europe's next MMA superstar so unhappy with his performance afterward?
Well, McGregor fancies himself a knockout artist, and on an evening in which the UFC handed out six $50,000 post-fight bonuses, McGregor is going back to Ireland minus any extra dough.
"I want to finish them out there, McGregor (14-2) said at the UFC Fight Night post-fight news conference. "I'm looking to get paid. We get paid when we get finishes. This promotion wants finishes. That's what I'm looking for."
The dapper McGregor, clad in a suit jacket, bowtie and designer sunglasses, pulled out a gold pocket watch for added effect.
"These custom-made suits aren't cheap," McGregor said. "This solid gold pocket watch, three people died making this watch. I need to put people away. I want to get paid. I'm going to go into debt fast, you know? I want to finish everyone, that's my program."
Thus concluded what was, without a doubt, the most unique week a UFC undercard fighter has experienced in recent memory. The UFC, which hasn't held a fight card in the Republic of Ireland since 2009, sees pots of gold at both ends of the rainbow: in McGregor's homeland, where he could sell out arenas now; and here in North America, where the lighter weight classes are in dire need of the sort of divisive drawing card whom half the fans love and the other half wants to see get knocked out.
"Trust me, we could put him in any arena in Ireland and sell it out," UFC president Dana White said. "But that wouldn't be the right thing to do. It's too soon to put him in the headline position. He's just 2-0 in the UFC."
McGregor's fight went on sixth out of 13 on the evening. But he was given his own media day on Tuesday, putting on a workout at the gym of noted Boston boxing trainer Peter Welch. Saturday, McGregor's ring entrance was accorded the sort of histrionics usually reserved for pay-per-view headliners: The house lights were drawn down and a light and laser show went off while McGregor walked to the Octagon to the sounds of the Dropkick Murphy's "I'm shipping up to Boston."
That's a small mountain of hype to live up to. But while McGregor's fans, who serenaded his fight with "olé, olé" chants, might have wanted a knockout, a mid-fight knee injury changed their man's plans.
McGregor dominated the first round with a kickboxing clinic. He worked the angles, mixed his punches and kicks and taunted Holloway in between. A knockout seemed inevitable. But somewhere in the second round, McGregor heard something pop in his knee.
"It feels like a loss to me, to be honest," McGregor said. "I wanted the finish. I felt the finish was there for me. I injured my knee midway through the second, and I just couldn't get it out of my head. But looking back, I should have just pulled my knee from my leg and hit him with it."
McGregor adjusted on the fly. He used his wrestling to score effortless takedowns. Once on the ground, his positional transitions were solid. While he didn't come close to finishing the fight, he earned judges' scores of 30-27, 30-27 and 30-26.
"I don't come here for decisions," McGregor said. "We are rewarded for finishes, and that's what I'm looking for. I'm a finisher. Anything else to me, other than stealing the show? I planned on stealing the show, and it didn't happen for me. It feels like I'm dealing with a loss at the minute."
Still, while McGregor isn't ready to see the silver lining in his performance, he did a handy job answering several of the skeptics' questions. Does he have a ground game? That's always the big question asked of fighters from the UK and Ireland, which is not a traditional wrestling hotbed. McGregor had his way on the ground with Holloway. How does he adapt under pressure? Even with his knee injury, McGregor went straight to Plan B and was never threatened.
But the Irishman didn't want to hear anything of it.
"I don't care what anyone in my weight class thinks," McGregor said, "I know what I can deal with. I know I do it in the gym day in and day out. I know people are thinking, 'Oh, you got in the three rounds.' [Expletive] I got the three rounds in. I get three rounds in a week. I could have done 20 rounds out there."…Dana giving me all this attention and putting this on me, these guys are making my dreams come true. I'm forever grateful to these guys. That's why this is a loss to me."
Long after McGregor had left the podium, though, his boss admitted he loved McGregor's response to the fight.
"I love that attitude," White said. "He's pissed off he didn't finish. Some guys will sit up here and go, 'Eh, well, I won.' No. He's pissed at himself that he didn't finish. Are you kidding me? Why am I promoting this kid? Why am I getting behind him? Because I love what he's about."