Warren Gatland always backs himself and has made some bold calls ahead of Saturday’s decider against the Wallabies. CARDIFF, WALES – OCTOBER 01: Head Coach Warren Gatland of Wales prior to the 2015 Rugby World Cup Pool A match between Wales and Fiji at the Millennium Stadium on October 1, 2015 in Cardiff, United Kingdom. (Photo by Laurence Griffiths/Getty Images) Warren Gatland has never been afraid of making big calls and it’s fair to say he’s made a couple for Wales’ crucial Pool A clash with Australia on Saturday.The Kiwi who dropped Brian O’Driscoll for a deciding Lions Test, and selected 13 Ospreys in his first game in charge of Wales, has gambled on at least two players out of position in his backline, while the combination of Justin Tipuric and Sam Warburton will have the task of slowing down the Australian back row.Starting role for Justin Tipuric alongside Sam Warburton. Photo: Getty Images.While Wales are already assured a place in the quarter-finals, victory on Saturday would set them up with a likely last eight clash against Scotland, followed by a potential semi-final against one of Argentina, France or Ireland.Lose and they will need to beat South Africa and probably New Zealand just to better their performance of four years ago.With that in mind, there was never any question of using this game to rest a few players and try to ease some of the injury concerns in the squad, and Gatland has been bold in his selection.After watching England get taken to the cleaners by Australia at the breakdown, he has gone for the dual threat of Warburton and Tipuric, with a slightly injured Dan Lydiate missing out.Of course the Wallabies will be without the suspended Michael Hooper, but Sean McMahon looked in fine form against Uruguay and will be tough to slow down at ruck-time, while the key man in the back row remains David Pocock.If Wales can win that battle – and their pace in the back row at least gives them a chance – we should see more of their backs with time and space.With their midfield decimated, Gatland has plumped for George North at outside centre, a position in which he has never entirely convinced at Test level. Whether it will be enough to beat the in-form Australians is another matter entirely, but Gatland won’t die wondering.Wales: Gareth Anscombe, Alex Cuthbert, George North, Jamie Roberts, Liam Williams, Dan Biggar, Gareth Davies, Paul James, Scott Baldwin, Samson Lee, Luke Charteris, Alun Wyn Jones, Sam Warburton (c), Justin Tipuric, Taulupe FaletauReplacements: Ken Owens, Aaron Jarvis, Tomas Francis, Jake Ball, Ross Moriarty, Lloyd Williams, Rhys Priestland, James Hook. LATEST RUGBY WORLD MAGAZINE SUBSCRIPTION DEALS George North switches to centre to face the Wallabies. Photo: Getty Images.Tevita Kuridrani was quiet against England, but Michael Cheika will certainly plan to use him to challenge North early and often.Other injuries in the squad mean a first appearance for Gareth Anscombe, who comes straight into the team at full-back.More of a fly-half at age group level for New Zealand, he arguably played his best rugby at full-back during a Super Rugby-winning season for the Chiefs, and offers a big boot at the back.That means Liam Williams is again shifted out to the wing, having recovered from his knock to the head suffered against England, with Alex Cuthbert desperately trying to recover some form on the other.Up front it’s all change with the squad’s most experienced player, Gethin Jenkins, left out entirely as Paul James is fit to make his first appearance of the tournament.Samson Lee replaces Tomas Francis on the other side of the scrum, which will be severely tested.The selection of Luke Charteris may help in that regard, with the giant lock having seemingly learned to use his frame both at scrum-time and in disrupting mauls, another major Wallaby weapon.