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 number eight'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 team-mate 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.
Jones replaced Stuart Lancaster four years ago stating his over-riding aim was to steer England to World Cup glory in Japan and that ambition could be reduced to rubble on Saturday. Itoje knows the stakes are high.
"It feels huge. This is a scenario I haven't been in before, which is partly why it is so exciting for me," the Lions lock said.
"When you are in it, you don't think about tomorrow or what I did three years ago.
"What's important is what is in front of you and what you have to deal with. Come Saturday, it will be the biggest.
"It's a little bit more exciting now. 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."
Itoje has won four Gallagher Premiership titles and three European crowns with Saracens, but accepts the World Cup is a different stage.
"The Saracens experience makes it a little more comfortable, but the greater the risk the greater the reward," Itoje said.
"I'm really excited for this weekend. I'm really excited to play. I'm excited to train. I'm just really enjoying the process at the moment.
"We're playing it day by day but our goal is to beat Australia on Saturday. We want to play well, we want to put a good performance in, but without a shadow of a doubt we're looking to beat them."
Itoje reveals that the match will be played to a chorus of sledging, with England team-mate Joe Marler particularly effective.
"There is always a bit of chat from most teams. Most teams have one or two players who enjoy the verbal battles. We haven't played Australia for a while but it never seems to be too ridiculous," he said.
"Joe Marler loves it. He loves his one-liners and he loves to get a reaction out of people.
"For me, the last time I remember when I played against him in the Premiership he was either clapping very aggressively to try and mimic me or he was shouting, 'Yes!'"