PERTH: Australia will start the third and final Test against South Africa with an entirely new pace attack after dropping fatigued Peter Siddle and Ben Hilfenhaus from the 12-man squad for match, which begins on Friday.

The pace duo toiled in baking heat for nearly five sessions as they tried to bring an end to South Africa's second innings at Adelaide Oval earlier this week after James Pattinson broke down with a rib injury during the match.

The match was ultimately drawn, leaving the series all square at 0-0 going into the Perth Test and Australia needing a victory to win the top test ranking back from the tourists.

“We think both guys are still quite fatigued after Adelaide,” Australia captain Michael Clarke told reporters on Thursday.

“It was a really tough decision, especially the way they performed in that last game ... but we need to do what's best for the team.

“We feel we've got a really good stock with the other four fast bowlers in the squad of 12. So we're still in pretty good hands. But we know we have to perform at our best for five days to win this test match.”

Mitchell Starc, Josh Hastings, Josh Hazlewood and Mitchell Johnson were named as the four fast bowlers in the 12-man squad while all-rounder Shane Watson has also declared himself fit for bowling duties.

Clarke said he would make his final decision after inspecting the pitch on Friday morning and did not rule out spinner Nathan Lyon retaining his place in the team.

If 2009 ICC World Player of the Year Mitchell plays, it would be the left-armer's first Test after more than a year of struggle with form and fitness.

The 31-year-old has an intimidating record at the WACA, where his swing bowling has netted him 30 wickets in four tests, including a first innings haul of 8-61 against South Africa in 2008.

Left-armer Starc is almost certain to play his fifth test after being 12th man for the first two matches in Brisbane and Adelaide, while Hastings, 27, and Hazlewood, 21, are both uncapped.

Clarke was clearly still shaken by Ricky Ponting's announcement that Perth would be his last Test but said he thought that would only further motivate the already highly motivated Australians.

“It's why you play this great game, I think Ricky's announcement will only give us more inspiration to do everything we can to try to win this game,” he said.

“It's more special now because it's been such a great, hard-fought series,” he added.

“It's the pinnacle. It's not very often you get the opportunity to go out and beat a team and go back to being the top test team in the world. We've got a lot to play for.”

Squad:

Michael Clarke (captain), Shane Watson, David Warner, Ed Cowan, Ricky Ponting, Mike Hussey, Matthew Wade, Nathan Lyon, Mitchell Starc, Josh Hastings, Josh Hazlewood, Mitchell Johnson.