#1 Eddie Alvarez
At UFC 205 at Madison Square Garden - the UFC's first event in New York following the sport's legalisation in the state a few months earlier - McGregor had the chance to make history by becoming the first fighter in the promotion's history to hold two belts simultaneously.
Standing in his way was lightweight champion Eddie Alvarez, who had defeated former champion Rafael Dos Anjos in spectacular fashion just a few months before.
Get the latest updates on One Championship Rankings at Sportskeeda and more
Alvarez, a pressure fighter with excellent cardio and good wrestling, was said to be a bad style match-up for McGregor, who had struggled with the similar high-tempo, in-your-face approach of Nate Diaz only a few fights earlier.
But this was a different McGregor. On his way to the Octagon, the Irishman cut a confident figure, his face a picture of composure despite the fact he was about to take part in the biggest fight of his life in front of a sold out MSG.
Right from the off, McGregor had Alvarez's timing down to a tee. Whenever the American swung, Conor was out the way and countering with that formidable left hand. When the bell rang for the end of the first round, Alvarez - who had been dropped no less than three times - was lucky to hear it, however, the fight wouldn't last much longer.
A couple minutes into the second stanza, McGregor countered with a beautiful four-punch combo that dropped his opponent once more, forcing referee John McCarthy to intervene to prevent the beleaguered Alvarez suffering any more unnecessary punishment.
McGregor had done it. He'd made history by becoming the UFC's first double-champion and he'd done it in style. The new champ-champ had made an elite fighter in Eddie Alvarez look like an amateur, and on the biggest stage of all in the world's most iconic arena he'd put on his best performance to date.
Send us news tips at [email protected].