A woman standing on her own waiting for an Uber in Rio de Janeiro may have appeared an easy target to a would-be thief.

Key points: UFC strawweight fighter Polyana Viana says she beat up a would-be mugger trying to steal her mobile phone

UFC strawweight fighter Polyana Viana says she beat up a would-be mugger trying to steal her mobile phone She says she judged he did not have a real gun as it was "too soft"

She says she judged he did not have a real gun as it was "too soft" Passers-by called police while she pinned her assailant, who was treated in hospital before being taken to the police station

The only problem for the perpetrator was his target was a strawweight UFC fighter, who turned the tables on the thief with punches, a kick and a "rear-naked choke" before forcing him to sit and wait for the police.

Mixed martial arts (MMA) fighter Polyana Viana, nicknamed "the Iron Lady", told website MMA Junkie the thief used a fake gun to try and steal her mobile phone while she waited outside her apartment block on Saturday night.

"When he saw I saw him, he sat next to me," Viana said.

"He asked me the time, I said it, and I saw he wasn't going to leave. So I already moved to put my cell phone in my waist.

"And then he said, 'Give me the phone. Don't try to react, because I'm armed.' Then he put his hand over [a gun], but I realised it was too soft.

"He was really close to me. So I thought 'if it's a gun, he won't have time to draw it.' So I stood up. I threw two punches and a kick. He fell, then I caught him in a rear-naked choke.

"Then I sat him down in the same place we were before and said 'now we'll wait for the police'."

Polyana Viana said she realised the gun the mugger was holding appeared "too soft", before she fought back. ( Supplied: Polyana Viana )

With her assailant subdued, Viana found the gun was in fact just a cardboard cut-out of a pistol.

She said she asked passers-by to call the police while she kept the man pinned.

Polyana Viana is known as "the Iron Lady" on the UFC circuit. ( Twitter: Polyana_VianaDF )

"I was fine because he didn't even react after. Since he took the punches very quickly, I think he was scared. So he didn't react anymore," she said.

"He told me to let him go, like 'I just asked for the time.' I said, 'Asked for the time my ass,' because he saw I was very angry.

"I said I wouldn't let go and that I was going to call the police. He said 'call the police, then', because he was scared I was going to beat him up more."

Viana said police took the man to a medical facility to treat his wounds and then to the police station, where she filed a report.

UFC president Dana White applauded Viana, tweeting an image of the fighter alongside the mugger.

"On the left is @Polyana_VianaDF, one of our @UFC fighters and on the right is the guy who tried to rob her #badf***ingidea," White tweeted.

Viana said she simply went home and made dinner after leaving the police station, adding her hands hurt a little the day after, but it was nothing serious.

Polyana Viana kept her assailant pinned down while passers-by called police. ( Supplied: Polyana Viana )

Loading...