SYDNEY, Sept 13 (Reuters) - Argentina already had grounds for confidence heading into their Rugby Championship test against Australia on the Gold Coast this weekend and the absence of Wallabies scrumhalf Will Genia has given them some more.
The Pumas have been impressive in their draw with South Africa and the defeat to New Zealand in their last two games, while Australia were humbled twice by the All Blacks before last week's scrappy 26-19 win over the Springboks.
Genia will be sidelined for six months after undergoing knee reconstruction on Wednesday and is the third Australia captain this season to be ruled out of the inaugural four-team southern hemisphere championship by injury.
The 24-year-old has played 29 of his country's last 31 tests and last failed to suit up for an Australia international when the Wallabies met Ireland in Brisbane in June 2010, a testament to his importance to the side over the last three seasons.
"I think he's been a talisman for them," Argentina prop Marcos Ayerza told reporters this week.
"To lose a key player... and a captain... is a massive loss for Australia and hopefully we can use that to our advantage."
Genia will be replaced at halfback by Nick Phipps for Saturday's match at Skilled Park and as skipper by lock Nathan Sharpe, who will lead his country in what will be his 109th test and the first to be played in his home town.
The 34-year-old Sharpe, who will retire at the end of this season, is the only Australian player to have previously played the Pumas.
There was a time when Australia's main concern when facing Argentina would have been how their often fragile pack would fare, but a major worry in the Rugby Championship so far has been the failure of their backs to score a try.
Coach Robbie Deans has rejigged his backline by bringing straight-running Pat McCabe back into the centres and moving Berrick Barnes to fullback in place of Kurtley Beale, who has been dropped to the bench for the second time in three matches.
For a side already struggling to get on the front foot, and for creativity behind the scrum, there could hardly be a worse team to come up against than the Pumas.
"The one thing they're very good at is stopping their opponents from playing. They're a very difficult side to play against," Deans said this week.
"No one's been able to create any momentum against them. That's obviously a big part of getting them into the game."
In the Australian forwards, a hamstring injury to Sitaleki Timani means a debut for Kane Douglas alongside Sharpe in the second row against an Argentina pack unchanged from the 21-5 loss to the world champions.
Argentina coach Santiago Phelan has also changed his scrumhalf and fullback with Martin Landajo making way for Nicolas Vergallo at the back of the scrum while Lucas Gonzalez Amorosino comes in for Martin Rodriguez in the number 15 shirt.
Ayerza has been dropped but the likes of number eight Juan Martin Fernandez Lobbe, flanker Julio Faras Cabello and prop Rodrigo Roncero will ensure a tough evening for the home side, and particularly for Phipps.
Argentina upset the Wallabies in their ever first test in Australia in Brisbane 29 years ago but have lost the subsequent eight matches between the sides.
Australia: 15-Berrick Barnes, 14-Dom Shipperley, 13-Adam Ashley-Cooper, 12-Pat McCabe, 11-Digby Ioane, 10-Quade Cooper, 9-Nick Phipps, 8-Radike Samo, 7-Michael Hooper, 6-Dave Dennis, 5-Nathan Sharpe (captain), 4-Kane Douglas, 3-Ben Alexander, 2-Tatafu Polota Nau, 1-Benn Robinson.
Argentina: 15-Lucas Gonzalez Amorosino, 14-Gonzalo Camacho, 13-Marcelo Bosch, 12-Santiago Fernandez, 11-Horacio Agulla, 10-Juan Martin Hernandez, 9-Martin Landajo, 8-Juan Martin Fernandez Lobbe (captain), 7-Juan Manuel Leguizamon, 6-Julio Farias Cabello, 5-Patricio Albacete, 4-Manuel Carizza, 3-Juan Figallo, 2-Eusebio Guinazu, 1-Rodrigo Roncero.
Referee: Wayne Barnes (England) (Editing by John O'Brien)