Weili Zhang brutally knocked out Joanna Jedrzejczyk with a perfectly-timed spinning back fist to leave the ex-UFC champion out cold in their rematch.

In round two of a fight that was shaping up to be a repeat of their first fight, the Chinese MMA fighter uncorked an incredible backhanded punch to close the show.

Jedrzejczyk, 34, was left face down on the canvas and referee Marc Goddard quickly swooped in to stop the fight.

The former UFC strawweight champion, who lost to her two-time foe two years ago, announced her retirement from mixed martial arts with immediate effect.

Jedrzejczyk left her gloves in the centre of the octagon after announcing her retirement at UFC 275.

She said: “I’m retired, guys.

“I love you so much. Thank you for this opportunity. UFC, Dana, so sorry I let you down.”

“I’m turning 35 this year. I want to be a mom; I want to be a businesswoman. I now want all of this to happen. I’ve been training two decades, more than half of my life. I love you guys.”

WATCH: Weili Zhang knocked out Joanna Jedrzejczyk with a superb spinning back fist

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And seconds after sending Jedrzejczyk into retirement, Zhang, 32, sent a message to current titleholder Carla Esparza.

“Carla Esparza, I heard there’s an event in Abu Dhabi, and I want to invite you to fight me Abu Dhabi," she said via a translator.

“It’s not your territory. It’s not my territory. Let’s be in Abu Dhabi and fight together.”

Prior to her stunning performance, Dana White revealed in an interview with Kevin Iole that the winner of Zhang's rematch with Jedrzejczyk will get the next title shot.

The UFC president told Yahoo! Sports: "It's tough to put that kind of pressure on this fight this weekend because when you see a fight like that, it's - you know, you're so lucky - and we were so lucky to have been there and actually saw that fight live.

"But yeah, I mean, it's impossible not to be excited.

"These two are both absolute savages. And I'm not putting the same expectations on this fight. But it should be damn good.

"What's even more incredible is, I mean, they're both still two of the top three women in the world. And we're going to get to see it again. So yeah, it's awesome.

"This weekend's going to tell a lot about both of these girls."