He announced his arrival on the New York scene with the most clinical display of power and precision yet.
But a whole other arrival might be about to put the breaks on Conor McGregor.
The Dubliner made a whole pile of history in Madison Square Garden with a terrific triumph in the headline act of UFC 205 in the early hours of Sunday morning, destroying lightweight champion Eddie Alvarez with a second-round knockout that, in truth, could have been delivered a whole lot earlier.
McGregor was dominant early and so often on a landmark night in the Notorious journey. More fighting landmarks, however, are likely to wait for a while. The 28-year-old has some personal matters to attend to.
With both belts sitting proudly in front of him - victory had made him the first fighter to ever take command of two divisions simultaneously - McGregor announced in the post-fight press conference that he will become a father in 2017.
It's a development that appears to have jarred him a whole lot more than Alvarez ever threatened to do.
"I'm going to be a daddy early next year," McGregor said. "I'm crapping my jocks. I'm not going to lie. I don't even know what way to take it. I don't want to be bringing a child into anything like this. I don't want any celebrity-type s***, I hate all that. I don't want my family to be like that.
"So that's a thing in the back of my head so I'm just going to have this baby, take a little bit of time and see what way I feel after that."
On a huge night for the UFC - pay-per-view records tumbled as the Garden's all-time gate fell too - some of its key figures lined up to challenge McGregor.
Welterweight champion Tyron Woodley, who retained his title with a majority draw with Stephen Thompson in the curtain-raiser, admitted he would relish a crack at the Dubliner.
So too did lightweight Khabib Nurmagomedov, another winner on the night.
But the most emphatic winner has family business to attend to first. And some pressing contractual matters too it seems.
McGregor revealed his frustrations at a lack of contact from the UFC's new owners in the wake of a $4 billion summer takeover.
"They've got to come talk to me now because no one has come talk to me since the sale has happened," he said. "I mean who owns the company now? People have shares in the company now, celebrities. Conan O'Brien owns the UFC now so where's my share? Where's my equity?
"I'm the one who's bringing this. They've got to come talk to me now. That's all I know. I have both belts, a chunk of money, I've got a little family on the way. You want me to stick around, to keep doing what I'm doing, let's talk. But I want ownership now."
UFC chief Dana White had earlier purred about McGregor's contribution. But platitudes are clearly not going to cut it.
"I've been happy to just continue doing what I'm doing but I feel I've out-worn the previous contract. I know I'm the highest-paid already but I'm looking at what they're taking in," said McGregor.
"That list that was compiled to show the new owners, that's like the gospel right there. That's proof of what I bring. You want me to stick around and help service that debt and continue to push the company? Bring me on board for real."
"I'm very satisfied, very grateful, very happy. But I'm not surprised. I knew it was going to happen for me."
It is quite often thus with McGregor in post-fight press conferences, as he and the wider UFC community immediately cast minds forward.
Perhaps the revelation of his soon-to-change circumstances spurred more of that talk than ever here. However, there were a couple of moments for reflection on how devastating a performance he had just turned in on the biggest stage he had known.
"It feels great. It feels familiar. I saw it so clearly, so consistently until it's here in reality," he said of a triumph that couldn't have gone more according to plan as he continually picked the perfect shots to slow and then stop the veteran Alvarez.
"I've been saying this a long time. I'm very confident in my abilities and what I'm predicting I'm going to do. I back it up with work ethic, hours upon hours of time, dedication. I never slip. I never take a second off this game.
"I'm very satisfied, very grateful, very happy. But I'm not surprised. I knew it was going to happen for me."
