Conor McGregor spent the days leading to his UFC return keeping a humble profile in stark contrast to his typical pre-fight bravado. The dynamic Irishman then made an emphatic statement inside the octagon Saturday night, disposing of Donald “Cowboy” Cerrone via stoppage 40 seconds into the first round of the welterweight headline bout in UFC 246 in Las Vegas.

The technical knockout in front of a sold-out, star-studded crowd at T-Mobile Arena was the second quickest in McGregor’s career behind the 13 seconds it took him to finish Jose Aldo in 2015.

McGregor (22-4) took the fight to Cerrone (36-14, 1 no contest) immediately, landing a shoulder strike in the opening seconds that bloodied the nose of UFC’s career leader in wins, finishes and performance bonuses. With Cerrone hurt, McGregor, 31, wasted no time throttling his veteran opponent while in a clinch before a high kick sent Cerrone back into the cage.

Another left hand sent the 36-year-old Cerrone to the mat, and not long after that strike, referee Herb Dean halted the proceedings, with Cerrone all but helpless to defend himself against the only simultaneous two-division UFC champion.

“I made history here tonight,” said McGregor, who indicated he wants remain at 170 pounds but welcomes any and all challengers. “I set another record. I’m the first UFC fighter to secure knockouts in featherweight, lightweight and now welterweight.”

McGregor was fighting for the first time since October 2018, when he lost via fourth-round submission to Khabib Nurmagomedov, also at T-Mobile Arena.

McGregor revealed he had been drinking throughout training camp leading to the fight against Nurmagomedov, leaving him unfocused and underprepared. He left no doubt against Cerrone, proving his skills have not eroded despite the extended layoff.

“I had never seen anything like it,” Cerrone said after the loss. “I got my ass whipped early.”