Wallabies aim to pump brakes on Fiji's 'Semi-trailer'

The Wallabies are looking to put the brakes on Fiji's Semi Radradra with the ex-NRL star in their sights in their Rugby World Cup showdown with a quarter-final berth on the line.

Known as "Semi-trailer", the hulking centre is Fiji's go-to man with the Pacific Islanders desperate to topple Australia in Saint-Etienne on Sunday (Monday AEST) to keep alive their tournament.

Radradra will need to regroup after fumbling a last-ditch pass that could have led to a match-winning try in their World Cup opener against Wales, instead falling 32-26.

Playing for Parramatta between 2013 and 2017, Radradra had a stunning strike rate with 82 tries from 94 games.

Wallabies assistant Jason Ryles said stopping Radradra would be key to Australia's hopes of banking back-to-back victories after downing Georgia in their first pool game.

Barring any major upsets a win over Fiji would see the Wallabies and Wales secure the two play-off spots.

"Semi's one of those guys that bend the line and they like to play off the back of him and in open space they look for him," said Ryles, himself a former NRL star forward.

"He's a huge influence on their team and one of the guys that we're certainly going to have to make sure we're doing a good job on."

Wallabies winger Suliasi Vunivalu got the better of Radradra in their last meeting in a 2017 NRL qualifying final, when the ex-Storm star helped his team to victory.

Radradra was one of the Eels' scorers in an 18-16 thriller at AAMI Park.

"I played against Semi back in club level at NRL and he's a big threat so I'm looking forward this week to playing him," said Vunivalu.

"We played each other in the finals and we (Melbourne) got up in 2017 so that was good.

"There's no banter (between us) - it's just respect."

One of seven players in the Wallabies squad with Fijian bloodlines, Vunivalu was born and raised in Fiji until he moved to New Zealand as a teen and then on to Australia.

He said he asked fellow Fiji-born winger Marika Koroibete, who was part of Australia's win over Fiji at the 2019 World Cup, if they would be targeted by the islanders.

"I was actually speaking to Marika about their last World Cup, and what they were saying, like 'Were they like trying to aim at them, like Fijian on Fijian?'

"He said they were mentioning stuff to Samu (Kerevi) like 'Belt him, belt him' in Fijian.

"And I was like, 'Did Samu know?' and he said, 'No, I didn't want to tell Samu about that' but yeah I think they'll be looking forward to the same situation this week."