Argentina feel their chances of an historic Rugby Championship triumph have been "massively" boosted by the Wallabies' latest captain's curse injury.

The Pumas have no doubt skipper and halfback Will Genia's season-ending knee injury leaves Australia vulnerable in Saturday night's Rugby Championship clash at Skilled Park on the Gold Coast.

Argentina have surprised with their competitiveness in their first three matches in the expanded tournament and are desperate for a first scalp.

While they have drawn with South Africa and rattled the All Blacks for an hour in a 21-5 loss in Wellington, the Wallabies have struggled to go close to their best and were far from convincing 26-19 winners over the Springboks on Saturday in Perth where Genia was hurt.

Back-up halfback Nick Phipps is sure to be targeted with pressure from the Pumas who had not doubt how much the Wallabies would miss Genia.

"Massively. I think he's been a talisman for them," said veteran Pumas prop Marcos Ayerza on Monday. "He's a very important player for them.

"To lose a key player like No.9 or 10 ... and a captain ... is a massive loss for Australia and hopefully we can use that to our advantage."

Phipps admitted he felt pressure but was excited and ready to fill the void despite having less than 100 minutes of Test experience across four caps.

"It's pretty bittersweet - you never want to see one of your boys go down, especially the captain," Phipps said.

"But now there's a hole to fill and hopefully I'll be able to do that for the boys as much as possible."

Genia has told Phipps to focus on doing the scrumhalf basics well but the Melbourne Rebels No.9 believed he was ready to do all that was asked in what will be a rugged encounter against the aggressive Pumas.

A part of the Wallabies squad for the past two seasons, Phipps has been reminded consistently by coach Robbie Deans his big chance would come.

"He always said it was only an injury away," the 23-year-old said. "He wanted me to treat every training (session) like a Test match and I've really gone in with a mindset like that.

"No one is going to sit around and say 'oh he hasn't really played much'.

"It's all right. You have to go straight in there and know absolutely that you're ready to play and you have to stand up."

Veteran lock Nathan Sharpe, a Gold Coast product, is expected to be named as Australia's fourth captain in less than four months when the Wallabies team is named on Tuesday.

Injuries have also put James Horwill (hamstring) and David Pocock (knee) on the sidelines.

James O'Connor (hamstring) is one star player ending his recovery period and rejoined the Wallabies squad on Monday.

O'Connor is targeting a possible return overseas against the Springboks (October 30) or Pumas (October 6) while centre Pat McCabe is available to play this Saturday night.