One of the biggest upsets in mixed martial arts just happened at UFC 193.

Ronda Rousey, who had won her last three title matches by a combined 64 seconds, was stunned by challenger Holly Holm in the main event at Etihad Stadium in Melbourne, Australia.

Holm dominated the first round with multiple big blows right to Rousey's head, and she continued that success in the second. Holm clinched the massive upset with a kick with her left leg, which knocked the former champion to the ground.

Unbelievable. Absolutely stunning. History has been made at UFC 193.

Thumbnail photo via Twitter/@UNIBETAustralia