In arguably the biggest upset in UFC history, Holly Holm knocked out Ronda Rousey on Saturday in Melbourne, Australia, with a kick to the head in the second round to become the women's bantamweight champion in the main event of UFC 193.

Rousey, who blossomed into a superstar with a series of spectacular finishes, was never in the fight.

A multiple time boxing champion, Holm easily won the first round by picking apart Rousey with her hands. Rousey's coach, Edmond Tarverdyan, said before the bout that he felt Rousey could outbox Holm, but that battle wasn't even close.

Holm circled, moving in and out, firing both lefts and rights, landing with great accuracy. Rousey kept moving forward, but her defense was loose and she didn't have much of an answer for Holm's accurate, precise strikes.

"I'm trying to take it all in, but it's crazy," Holm said before breaking into tears.

Rousey got Holm down one time in the first round, and went after her famous arm bar. But Holm easily escaped and that was pretty much the extent of Rousey's offense.

At one point, Holm took Rousey down before immediately bouncing up.

When the first round ended, Rousey walked back to the corner and was clearly winded, bleeding from the nose and mouth. But she didn't do anything different in the second.

She attacked again when the bell range, but Holm again belted her from range. A Holm left badly hurt Rousey and spun her around. Holm put her arm on Rousey and turned her, then fired a kick to the head and Rousey went down hard, clearly out.

Holm went after her and landed a couple big punches from the top before referee Herb Dean stopped it.

"I just had so much help with everything," Holm said, who was as high as an 18-to-1 underdog before getting a lot of late wagering action.