Billy Vunipola has won his battle to be fit for England’s World Cup quarter-final against Australia at Oita Stadium.

Vunipola came through the toughest training session of the week on Wednesday, the PA news agency understands, to complete his recovery from the ankle sprain sustained in the pool victory over Argentina that secured passage into the knockout phase.

Head coach Eddie Jones is likely to name Vunipola in the back row as part of an unchanged starting XV, knowing the Saracens No.8’s powerful ball-carrying could be a key asset against the Wallabies.

Jones announces his team on Thursday and there is expected to be an adjustment on the bench with Jack Nowell losing out to a hamstring injury, creating an opportunity for Jonathan Joseph.

Vunipola’s Saracens teammate Maro Itoje, meanwhile, is ready to embrace the biggest game of his career admitting the looming clash with Australia is win or bust.

England will be looking to complete a seventh successive victory over the Wallabies, who enter the encounter battle-hardened by a tougher group campaign.

“It feels huge. This is a scenario I haven’t been in before, which is partly why it is so exciting for me,” Itoje said.

“Now that it’s knockout rugby there’s no tomorrow here. It’s do or die. There’s no, ‘We’ll get it right next week’. It’s about performing.”