Conor McGregor backed up every word he ever said to Jose Aldo with one spectacular punch.

McGregor stopped Aldo with a left hand to the jaw just 13 seconds into the first round Saturday night, claiming the undisputed featherweight title at UFC 194.

McGregor (19-2) finished the fight with an electrifying exchange shortly after the opening bell, slipping Aldo’s lead right and cracking the champ with his formidable punching power.

Aldo (25-2) actually finished his punch and hit McGregor with a left, but the champ fell senseless to the ground. McGregor pounced, only to be pulled off in his fifth consecutive knockout victory.

“What I say happens, happens,” McGregor said. “There is no doubt now.”

Aldo had won 18 consecutive fights over the last 10 years, but not even the only previous 145-pound champion in UFC history could survive McGregor.

The loquacious Irish brawler goaded Aldo throughout the promotion of their delayed bout, only to earn a victory that was even more dramatic than he predicted. McGregor’s victory was the fastest title fight in UFC history, surpassing Ronda Rousey’s 14-second win over Cat Zingano at UFC 184 in February.

“Precision beats power, and timing beats speed,” McGregor said. “Jose was a phenomenal champion. He deserved to go a little bit longer, but I still feel at the end of the day, precision beats power and timing beats speed. That’s what happened.”