NEW YORK — T.J. Dillashaw competed in just about the most hostile environment he could possibly have faced. Dillashaw fought Cody Garbrandt, his former teammate, with all of his former coaches in the opposite corner.

The crowd at Madison Square Garden was so against him that it was chanting, “[Expletive] you, T.J.!” in the second round.

But none of it fazed Dillashaw, who stopped Garbrandt and put a temporary end to their bitter rivalry with a shocking ending in the co-main event of UFC 217 in their bantamweight title fight.

Dillashaw landed a kick to the head that dropped Garbrandt, who seemed poised to become one of the UFC’s most popular champions. Garbrandt got up, but Dillashaw caught him with a right hand that dropped him again. Dillashaw followed him to the floor and after a bit of ground-and-pound, referee Dan Miragliotta stopped it at 2:41 of the second.

That returned the belt to Dillashaw, but he had nothing but good things to say about his vanquished rival and ex-teammate.

“He’s a hell of a fighter,” Dillashaw said. “He’s young and he’s going to be back. I’ll see him again.”

It was a fast and ferocious first round, and Garbrandt got the best of it. He dropped Dillashaw with a right hand late in the round and when the bell sounded, it took Dillashaw a while to get his bearings.

He staggered back to his corner, unable to walk a straight line. But he’d recovered by the time the second started.

“I got caught with a right but I bounced right back,” Dillashaw said.

Dillashaw, who used his kicks throughout the fight, connected with a left kick to the head that for all intents and purposes ended it.

Garbrandt, who lifted the title from Dominick Cruz at UFC 207 last December and was making his first title defense, showed his courage and toughness by pulling himself off the canvas.

But Dillashaw knew this was his opportunity and he didn’t let it pass him by. He connected with a solid right hand that again dropped Garbrandt and it was over seconds later.