Australia v South Africa, 3rd Test, Perth November 29, 2012

Australia's No.1 hopes could rest on new-look attack

Australia could enter their grand final against South Africa - and Ricky Ponting's farewell Test - with a completely different attack from the one used in Adelaide, after Peter Siddle and Ben Hilfenhaus were ruled out. Siddle and Hilfenhaus both endured heavy workloads at the Adelaide Oval, where James Pattinson's side injury left Australia one bowler short for most of the match, and the selectors were unwilling to risk them in the decider given the narrow gap between Tests.

That means Australia's chances of reclaiming the No.1 Test ranking, which will be theirs with victory at the WACA, will rest on an attack featuring four of Mitchell Johnson, Mitchell Starc, Nathan Lyon, Josh Hazlewood and John Hastings. The offspinner, Lyon, has been included in Australia's 12 but his fate won't be decided until the morning of the match, and a four-man pace attack including the uncapped Hastings and Hazlewood is a distinct possibility.

"At this stage we're only announcing 12. I want to see the conditions tomorrow," the captain Michael Clarke said on Wednesday. "The two players that aren't part of that 12 are Peter Siddle and Ben Hilfenhaus. We think both guys are still quite fatigued after Adelaide. We've selected that 12 to give ourselves the best chance of winning this third and final Test match against South Africa.

"[It was a] really tough decision, especially the way both performed. Especially Sidds, the way he performed in that last Test match. But we need to do what's best for the team. It's about selecting the best XI players to win this Test match in these conditions. We feel we've got a really good stock with the other four fast bowlers in the squad of 12, so I think we're still in pretty good hands."

Starc and Johnson, who hasn't played a Test since November 2011, are expected be included, with Hazlewood and Hastings likely to battle for one position if Lyon gets the nod. The Australians chose an all-pace attack at the WACA last summer and had great success, demolishing India within three days, but Clarke said Lyon was still well and truly in contention for a place in this match.

"He's still a chance, that's for sure," he said. "The wicket looks pretty good and I always like having a spinner in the team. Over a five-day period spin will play a part. It does at the Gabba and the WACA. But we need to work out what our best attack is to take 20 wickets. If we think Nathan is part of that, then we go with Nathan. If not, we have the option of going with four fast bowlers."

Whatever Australia's selectors decide, they will have at least one debutant to wear the baggy green alongside Ponting in his 168th and final Test. There is no question it will be an emotional match for the Australians, but they must ensure the feeling surrounding Ponting's farewell does not dim their appreciation of what is up for grabs in this game. If they win, they will return to the top of the Test rankings for the first time since July 2009.

"I think it will only give us more inspiration, there's no doubt about it," Clarke said of Ponting's retirement. "It's a grand final for us. It's why you play this great game, it's the thing you look forward to as a player, to be able to play this third and final Test match against the No.1 team in the world and know if you win, the greatest rewards are to be the No.1 team in the world. Ricky's announcement will only give us more inspiration to do everything we can to try to win this game.

"It's the pinnacle. It's not very often in your career you have an opportunity to beat a team and go back to No.1 Test team in the world. We've got a lot to play for. On the other hand, I don't think there's pressure on us. We can go out and play with freedom, play with confidence. We know we've competed really with South Africa over the first two Test matches. We really love playing in these conditions here at the WACA, a bit more pace and bounce in the wicket."

Not that either side has seen much of the pitch over the past couple of days. Rain showers have meant the covers have often been required, and Clarke said that his glimpse of the playing surface told him it would be a different story to the Adelaide Oval pitch the sides met on last week.

"I think it's going to be tough going for the batters throughout the whole Test match," Clarke said. "It might change with a bit of wind around today, and some sunshine, it might dry out a little bit more."

Brydon Coverdale is an assistant editor at ESPNcricinfo. He tweets here