Wallabies achilles heel now a strength

London - In his first news conference after taking over as Australia coach a year ago, Michael Cheika said one of the biggest jobs he faced was fixing the weakness in the Wallabies scrum.

On Saturday, he reaped the rewards for his hard work when a competitive set piece helped lay the foundations for a 33-13 victory over hosts England that sent Australia into the quarter-finals of the Rugby World Cup.

Refusing to crumble as Australian forwards have in the past after early setbacks, his pack stepped up their efforts and by the end of the game, reduced what was until recently one of the most highly regarded scrums in world rugby to disarray.

England were even reduced to replacing prop Joe Marler after he was penalised for the angle of his scrummaging, one of a string of calls Australia won from referee Romain Poite.

"The Aussie scrum was magnificent," England's World Cup winning coach Clive Woodward said.

It was no accident.

Cheika was fortunate in being able to welcome back hooker Stephen Moore from injury but he has also overhauled his front row by jettisoning stalwart props Benn Robinson and Ben Alexander and bringing through young loosehead Scott Sio.

The need for a second row to lock up the tighthead side of the scrum was the reason Kane Douglas was rushed straight off the plane from Ireland and into the squad after he cut short his stay at Leinster to return to Queensland.

Cheika brought in Argentine scrummaging coach Mario Ledesma to work on technique and ensuring that all eight men in the pack made a contribution to the scrum.

The first sign that a major improvement was in the works came when the Wallabies matched the All Blacks at scrum time during their victory over the world champions in Sydney in early August.

There have been false dawns for the Australian scrum before, however, and Cheika was not about to get carried away even after knocking England out of their own tournament.

"Like I've said before, and Mario's taught me this, the scrum's a very humbling part of the game because you can dominate one and get your pants pulled down in the next one if you're not on top of the game," he said.

"You've got to try to be consistent and yeah, okay, that went well for us tonight but we've got be consistent with it again next week.

"Because every time you take your eye off that ball with that stuff, everyone's improving and everyone's a threat, and we've got to be ready for the challenge we see from Wales in that area in the next game."