UFC 300 fight plunged into controversy as Joe Rogan asks 'are you allowed to do that?'

There was major confusion during one fight at UFC 300 after the commentary team questioned whether a fighter had used a substance during the bout.

UFC celebrated its 300^th pay-per-view event in style on Saturday night with an incredible event in Las Vegas.

Max Holloway's stunning KO win over Justin Gaethje won Fight of the Night, while Alex Pereira knocked out Jamahal Hill inside one round to retain his light heavyweight title in the co-main event.

But there was a confusing moment in the other co-main event between Zhang Weili and Yan Xiaonan.

Weili twice came within seconds of finishing Xiaonan, retaining her strawweight title with a comfortable decision victory.

At the end of the first round in their historic all-Chinese title fight, Weili caught her opponent's neck in a tight rear-naked choke.

Xiaonan appeared to momentarily lose consciousness. However, the referee did not stop the bout and allowed Xiaonan to rise to her feet at the end of the round and return to her team.

As she sat down on her stool, water was poured on her head and a coach appeared to touch her face.

The UFC's commentary team of Daniel Cormier and Joe Rogan questioned whether smelling salts had been used to wake Xiaonan up ahead of the second round.

There was a confusing moment in Zhang Weili's title fight with Yan Xiaonan (Image: Getty)

Cormier said: "In the corner, the cut-man said, 'I can wake her up' and then he gave some smelling salts or something."

Joe Rogan responded: "Oh no, really? Wait a minute, are you allowed to do that?"

However, the UFC's lead commentator, Jon Anik, later confirmed that smelling salts had not been given to Xiaonan after viewing the footage.

The incident made no difference to the final result, with Weili's strong wrestling enough to secure her the victory with scorecards of 49-45, 49-45, 49-45 in her favour.