UFC 269: Kamaru Usman, Tony Ferguson and more react to Julianna Peña's upset victory over Amanda Nunes

Julianna Pena shocks the MMA world, upsets Amanda Nunes at UFC 269 (1:16)

Julianna Pena defeats Amanda Nunes to win the UFC women's bantamweight title, one of the biggest upsets in UFC history. (1:16)

The women's bantamweight championship fight at UFC 269 produced the biggest upset we've seen in the sport in a long time.

Julianna Peña shocked the world Saturday night when she defeated Amanda Nunes by submission in the second round of their co-main event fight at T-Mobile Arena in Las Vegas. A rear-naked choke did in the now former women's bantamweight champion after Peña landed jab after jab to weaken Nunes. As a result, Pena becomes the fifth champion in this division, following Ronda Rousey, Holly Holm, Miesha Tate and Nunes.

Peña said she'd bring the fight to the 33-year-old Brazilian fighter, and that's exactly what she did. She pulled off one of the biggest upsets in UFC history, and T-Mobile Arena erupted after witnessing the result of the shocking co-main event.

Social media also offered their commentary on the Peña's upset, including athletes, celebrities and more: