Chris Robshaw believes Eddie Jones will have a "big impact" on Australia after taking charge of the Wallabies for a second time following his sacking by England.
Just weeks after his dismissal following a dire run of results, veteran coach Jones is back at the helm of his native Australia, having been their boss when they lost the 2003 World Cup final to England in Sydney.
The teams could meet in the last eight of this year's edition in October, leaving open the prospect of England suffering a defeat overseen by the man who took them all way to the 2019 final loss to South Africa in Japan and was contracted to be in charge of the Red Rose brigade at France 2023.
Former captain Robshaw played under Jones early in his seven-year England reign and has no doubt about his ability to raise Australia's game.
"We've seen Eddie's comments that Australia might see England in the quarter-finals -- and give a little smirk!," Robshaw told reporters on Wednesday.
"You always want to get one over your former team. I'm pretty sure Eddie will have a big impact. When any good coach goes into a different set-up it's bad news if it's not your team. Warren Gatland going back to Wales makes them tougher opposition straight away."
England may won just five of their 12 Tests under Jones in 2022 but the early years of his reign were an undeniable success.
Taking over after England's woeful group-stage exit on home soil at the 2015 World Cup, he led the team to a Six Nations Grand Slam and a series whitewash of Australia as part of a record-equalling run of 18 successive Test wins by a leading rugby union nation.
Robshaw, 36, said Jones' ability to lift a team straight from his appointment was unsurpassed in his experience.
"It's Eddie mentality," explained the recently-retired flanker.
"He was better than any coach I have worked in terms of his man management. And it wasn't always the big things, it was the little things like interacting with everyone every single morning in the breakfast room -- going around all the tables.
"He would treat all the players differently. With someone like myself he was always very honest, with someone like James Haskell they would always take the mick out of each other. He interacted with the person rather than just the rugby player."
Robshaw added: "For Australia, he will definitely have that ability to shake them up because they have good players but they are just low in confidence.
"They had a tough autumn series over here. The writing has been on the wall that at some point he would go back to that Australia job.
"He's a proud Australian, he's got a lot of history and heritage there. It's just happened a bit sooner than most had thought."