Amanda Nunes has accepted a rematch against Julianna Peña after her shock defeat at UFC 269.

In one of the biggest upsets in MMA history, Peña stunned Nunes to take the UFC women's bantamweight title last weekend.

Nunes was expected to easily win the bout at UFC 269, and she started strongly. She was unable to maintain this pace, however, and a rear-naked choke sealed the win for Peña mid-way through the second round.

UFC President Dana White confirmed Nunes would be offered a rematch, and the 33-year-old has appeared to accept it.

"You guys think I’m going to go out unbalanced," Nunes wrote on Instagram. "I undoubtedly accept the rematch.

"Give me a little time to get my shit together and I will be back better than ever."

Peña, who was full of confidence in the run-up to the fight against Nunes, has also agreed to a second fight.

"Amanda is the only matchup I think that makes sense for me and giving her that rematch," she said.

Nunes, who is still the UFC Women’s Featherweight Champion, saw her impressive 12-fight, seven-year undefeated streak come to an end at the weekend.

Amanda Nunes has accepted a rematch with Julianna Pena

There was speculation she had a fight against Kayla Harrison in the pipeline, but her loss to Peña has cast this into doubt.

"For a Kayla Harrison, the Amanda Nunes fight was huge," White said. "If they would have faced off, it would have been a massive, mega-million dollar fight.

"Let me tell you, if Amanda Nunes had won tonight, the Kayla Harrison fight would have been one of the biggest fights that you would have ever seen."

Harrison, a two-time Olympic judo gold medallist and two-time PFL champion, is currently a free agent.

The 31-year-old has been tipped to sign with UFC, and this speculation only increased when she was shown on the screen during the UFC 269 broadcast.

Julianna Pena stunned Amanda Nunes at UFC 269

Harrison could still sign with White's promotion company, but she would likely have to wait for the rematch to take place before taking on Nunes.

If Harrison were to sign with UFC, she would fight in the featherweight division.

Peña, who has repeatedly claimed she would not move up a weight class, did not seem tempted to do just that in order to to fight Harrison.

"I think she’s the lesser of the training partners for her and Amanda Nunes," Peña said. "If that’s the case and I just took out Amanda, I don’t know what kind of position that would put her in.

"But she’s been fighting the B-leagues. I’ve been fighting in the UFC, I’ve been fighting at the top of the division.

"I’m fighting in the biggest league of this sport so I’m not paying too much attention to what she’s doing down there."