Rival coaches Eddie Jones and Michael Cheika have both sprung selection surprises heading into a “do or die” World Cup quarter-final between England and Australia but there are sound reasons behind their dramatic decisions.

Jones has dropped in-form fly-half George Ford to the bench for Saturday's crunch game in Oita, with captain Owen Farrell moving from inside centre to stand-off.

Farrell, however, has plenty of Test experience at fly-half, where he plays for English and European champions Saracens.

By moving Farrell, Jones can pair Manu Tuilagi and the fit-again Henry Slade in midfield, a combination of power and guile he deployed during the Six Nations that also offers increased defensive solidity in an area of the pitch where Australia are strong in attack.

And should England need him to close out the match, they still have the option of bringing Ford off the bench. “Australia defend a certain way and we believe those players can trouble their defence,” said Jones, the Wallabies' coach when they lost the 2003 World Cup final to England.

“Defensively we feel that 10-12-13 (fly-half, inside centre, outside centre) combination is a strong combination.” Jones, a consultant to the South Africa side that won the 2007 World Cup and the coach of Japan when they stunned the Springboks in England four years ago, knows better than most about the demands of knockout rugby.

And with his four-year reign as England coach hinging on the team's progress at Japan 2019, the Australian said: “No one has won a World Cup after losing a game and there's a reason for that. “You know it's do or die time,” he also told reporters at England's hotel in Beppu.

“You see those hills at the back of us? That's where all the samurais lived. Every time the samurais fought, one lived and one died.

“It will be the same today -- someone is going to live and someone is going to die.” With powerhouse number eight Billy Vunipola recovered from an ankle injury, England will hope “kamikaze kids” Tom Curry and Sam Underhill can star at the battle of the breakdown against celebrated Australia duo Michael Hooper and David Pocock. Behind the scrum, they will look to Farrell to direct operations as they try to contain the threat of Australia's strong-running Fiji-born centre Samu Kerevi.

“Owen's got quite a big job for us. He's captain and he's goal-kicker,” Jones said.

“But I feel like sometimes, maybe earlier in the tournament, he spent too much time in the captaincy area and not enough on his own individual prep.

“I've seen a real change in that this week,” added Jones, whose side's final pool match against France was cancelled because of Typhoon Hagibis.

“He's a warrior. He leads from the front. He competes, he's tough.” The 2015 World Cup saw an Australia side coached by Michael Cheika go all the way to the final after they ended hosts England's involvement at the pool stage with a 33-13 win at Twickenham.

That prompted England to bring in Jones and they have since won all six of their Tests against Australia, still coached by Jones's former Randwick team-mate Cheika.

If doing the same thing repeatedly and expecting a different result is a sign of madness, Cheika's bold move in handing the 19-year-old Jordan Petaia a first Test start at centre is evidence of his determination to shake things up.

“He is more than ready to do this,” said Cheika, who has opted for Will Genia and Christian Lealiifano as his half-backs, with Kurtley Beale passed fit after a head injury. “I trust him infinitely, and that's why he has been chosen. “-AFP