CONOR McGregor blamed extended spells away from the UFC for his shock defeat to Dustin Poirier but the Irishman said "don't write me off yet" as he vowed to carry on in mixed martial arts.
McGregor beat Poirier inside two minutes in September 2014 and just over two years later he became the first fighter to simultaneously hold two UFC titles after adding lightweight gold to his featherweight crown.
Fame and fortune came amid a crossover boxing bout against pound-for-pound superstar Floyd Mayweather but, having reversed his retirement decision, his return bout with Poirier at UFC 257 at Fight Island in Abu Dhabi was just his third since November 2016.
He has had just 40 seconds in the octagon - a blow out of Donald Cerrone 12 months ago - since losing to bitter adversary Khabib Nurmagomedov in October 2018 and his hopes of luring the Russian into a rematch are in tatters.
His rhythm was disrupted by several kicks to his lead leg and he was then floored by a short right hand before Poirier landed another couple of heavy blows to force a dramatic stoppage midway through the second round.
"It's heart-breaking and hard to take," said 32-year-old McGregor, who turned up to the post-fight press conference on crutches.
"If you put in the time in here, you're going to get cosy in here and I just have to dust it off and come back and that's what I will do. I need activity, you don't get away with being inactive in this business.
"As long as you stay active and as long as you compete, things shape around you. You show up, you reap the rewards. That's what happened for Dustin and it's what's happened against me.
"I'll keep my eyes on the prize. Don't write me off yet, I'll make my adjustments and keep moving. I'll go back, get healthy and I'll re-prepare. I've got to a great place in my body physically and I'll continue to grow that."
McGregor had warned Nurmagomedov "the world knows this war is not over", despite the Russian bowing out of the sport last October after extending his perfect professional record to 29-0 with a win over Justin Gaethje.
UFC president Dana White had indicated the lightweight champion could be tempted to make a comeback if he saw "something spectacular" between the two headliners in front of 2,000 socially-distanced fans at the Etihad Arena.
However, White revealed he had spoken to Nurmagomedov following the fight and said: "He said to me 'be honest with yourself, I'm so many levels above these guys, I've beaten these guys'. It doesn't sound very positive. We'll see."
In the moments after McGregor's defeat, Nurmagomedov took to Twitter to accuse his foe of abandoning those who had helped him become the highest-profile fighter in the company.
McGregor gave short shrift to those allegations, saying: "My team has been the team since day one, I've not changed anything. That's the character of the man, for sure. What does he want to do, does he want to come back or not?
"If he wants to have his disrespectful comments, come back and let's go again, my man. I'm here for it. That's fighting talk. If you're coming back, come back - you try and do it."
McGregor (now 22-5) raised the prospect of trilogy bouts with Poirier or Nate Diaz, having now won once and lost once against both fighters. Poirier himself would relish another bout with McGregor or a showdown with Diaz.
"A rematch with Conor interests me, you probably have to do it again," said Poirier. "I've always wanted to whip Nate Diaz's ass. Me and Conor are one and one. We'll see."