LAS VEGAS — Julianna Peña called her shot and scored one of the biggest upsets in MMA history Saturday at UFC 269 at T-Mobile Arena.

After being dropped twice in the first round and fighting the last half of it with black belt Amanda Nunes going for a submission, Peña made history in the second.

She came out in the second round and stood toe-to-toe with the hardest-punching woman in the UFC and came out on top. They exchanged huge shots before Peña dropped Nunes and then quickly submitted Nunes with a rear naked choke at 3:20 of the second round in their bantamweight title fight in the co-main event of UFC 269.

Peña had said she had the style to beat Nunes and proved she knew what she was talking about.

“I told you!” said Peña, who was a +625 underdog at BetMGM. “Don’t ever doubt me again. Willpower, strength and determination will take you places.”

Nunes controlled the first round. She dropped Peña seconds into the fight and then about 90 seconds into it. She later got Peña's back and was working for a rear naked choke.

But when the second round began, it was a different fight. Peña, who was calmly dancing to Nunes’ walk-out music as the champion headed to the Octagon, decided to exchange with Nunes.

Both were landing, and that might seem to many a bad strategy given how hard Nunes hits. And sure enough, Peña's left eye was swelling. But Peña, remarkably, didn’t wilt. Instead it was Nunes.

She dropped Nunes, who went down on her stomach, and got Nunes’ back. Peña put in the rear naked choke and Nunes quickly tapped.

It is one of the biggest upsets in the UFC, similar to Matt Serra knocking out Georges St-Pierre and Holly Holm upsetting Ronda Rousey.

Nunes, who came into the bout widely considered as the greatest women’s fighter of all-time, made no excuses.

“I have to go back to the gym, train hard and get the next one,” she said.

But this time, she’ll do it as a challenger to the new champion, Julianna Peña.