【Monica Swinn】

Michelle Nicolini is Monica Swinnan eight-time world champion in BJJ (Brazilian Jiu-Jitsu) and a third degree black belt holder with 20 years of martial arts experience.

You'd never know it if you ran into the petite professional fighter in the street.

On Friday, she's up for one of the biggest challenges in her martial arts career.

Having built up years of experience as an expert grappler, she'll have to defend herself against powerful Muay Thai kicks and punches when she competes in the One Championships -- her first professional MMA competition.

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Nicolini, who moved to Singapore from Sao Paolo in August to teach BJJ at the Evolve MMA gym, has been training up to three times daily to handle the new kinds of assault.

Women as effective fighters

Nicolini says women often get terrified at the idea of having to defend themselves, and most worry they'll get overpowered.

"As a small person and not the strongest, I adapted my (BJJ) game to protect myself from injuries.

"I tell women, don't try to exchange power with the big guys. Move yourself out from different angles."

Women also tend to forget that their legs are stronger than their arms, and they should be kicking to push attackers away.

Here's a quick move if someone grabs you from behind -- knee to the groin, and run away, she says.

Nicolini also showed a couple of classic BJJ moves. In this shoulder lock, she stretches the opponent's arm until he submits.

During the World 2014 Jiu-Jitsu Championships, this move broke her opponent, Tammi Musumeci's arm, when the latter didn't tap out, and the referee kept the fight going.

You can see the arm broken at an angle at the 13 minute mark. It's fairly graphic, so we won't embed it.