With one loss to Diaz already in the books, McGregor risked suffering back-to-back defeats at a weight class two divisions above the one he reigns over as champion -- an unprecedented scenario that would have done irreparable harm to McGregor's image as one of the best fighters in the sport. And after besting Diaz with a gutsy decision win on Saturday in the rematch, McGregor acknowledged just how much his critics pushed him.
"This was a hell of an important fight for me," McGregor said at UFC 202's post-fight press conference. "Everyone, from the media to the fighters, wrote me off for this one. They tried to say if I lose this one, I'm done. They tried to discredit the fact that I'm going up in weight. He was 25 to 30 pounds heavier than me, I don't care what anyone says. He was a big boy in there. He was easily 190 pounds. I was 167 leaving for the fight and I was saying to myself, I need to eat, try and get up at least over 170.
"But it was a hell of a fight and he's a hell of a competitor. The whole lot of it brought out the best in me. It forced me to look at myself truly. I'm just grateful."
This time around was far different than the last time for both McGregor and Diaz. Rather than fighting on 11 days' notice like they did at UFC 196, the two rivals had over five months to prepare for one another as well as the welterweight limit both fights were contested at. And for both McGregor and Diaz, those extra months mattered in more ways than one.
"He got even bigger from the first fight," McGregor said of Diaz. "He was way bigger than the last time, so over that five months or whatever it was since the last fight, he grew. So I knew I was up against it and I was thinking in my head maybe this could be a mistake, but I said f*ck it, I train hard, be smart, learn from your mistakes, go in confident. And that's what we did, and I'm happy with it.
"It was a hell of a camp, hell of a preparation, and we got it done tonight. It was not easy. It was a war. I'm happy it went that way. I got to show my heart in there. I took it to him and I stayed in it and got the win, so I'm very happy with it."
Similar to their first fight, McGregor controlled the early exchanges at UFC 202 before slowing down near the end of the second round. Rather than wilt, though, McGregor survived and battled back to unanimously win the fourth frame to secure a 48-47 advantage on two of the three judges' scorecards, claiming a majority decision win with a performance than showcased a major evolution in the Irishman's game.
"Three times, I think I dropped him," McGregor said. "I could've gone in there and pressed, but I was thinking, I was patient. I learned that lesson. He does this thing where he uses his range where he pulls, and then as the fight progress he steps in. So when I anticipate that he's going to be far, he steps in close.
"That was one thing that flustered me in the first contest, because I was anticipating him to be far and then he was here. So I anticipated that a bit better and I was lighter with my shots and slapping a bit, but I just had to be patient, not fall into my shots, not rush. I anticipated him to be there for the full five rounds and he was, so the gameplan worked like my coach John Kavanagh's book, which is in stores now. Win or Learn. We learned this time and that's it. I'm very grateful for it."
With a win over Diaz now in his back pocket, McGregor has plenty of options at his disposal moving forward. He could venture back down to featherweight to defend his UFC featherweight title against Jose Aldo, as UFC president Dana White wants him to do, or McGregor could continue to explore fights at lightweight, whether it's a title fight against UFC champion Eddie Alvarez or a big-money rubber match against Diaz.
Either way, McGregor believes he proved his point to all of his peers that reveled in his first stumble.
"Just the way it all went down, I'm sitting back and looking at everyone," McGregor said. "I don't what anyone says, I helped bring this game to another level. They can deny that all they want, but I did. Look at Nate's purse tonight. Look at Nate's purse after the first fight. Look at everyone's. Everyone's game has gone up money-wise, and I helped do that.
"So after that fight when I lost and I'm looking at all of these people and they're all celebrating my demise and saying I'm done and this, it certainly lit a fire under my belly. Every single person doubted me. Every single fighter doubted me. Doubt me now."