And the crowd will be on his side with the Melbourne Cricket Club saying it is optimistic of a world record for a day's Test cricket after public sales for day one officially sold out at lunchtime on Wednesday. The record of 90,800 was set during the Australia-West Indies Test in 1961.

Clarke said Ryan Harris and his fellow fast bowlers were fit, but Australia would not announce its team until the toss on Boxing Day morning.

Harris has been battling knee soreness throughout the series, but joined in the Australians' optional training session on Christmas Day. In his column for Fairfax Media today, Harris declares he expects to play at the MCG, where he broke down in the corresponding Ashes Test three years ago.

"We've got at this stage the same 12 for tomorrow's Test match [including all-rounder James Faulkner]. We'll announce the XI tomorrow at the toss, but at this stage everyone seems fully fit," Clarke said.

"I think it's more about assessing the conditions tomorrow morning before we announce our XI."

Fast bowling reinforcements Doug Bollinger and Nathan Coulter-Nile are also with the squad.

Clarke refused to be distracted by the turmoil of the England players, who were rocked by the mid-series retirement of Graeme Swann this week. Nor has he detected any signs of complacency among his own troops, despite the 3-0 scoreline.

''Not at all,'' he says. ''I've said that 45 times in the past week. We're ranked fifth in the world. We've won three Test matches in the past 12 months. There's no complacency at all. This Test is as important as Brisbane was.''

A 4-0 series win would be enough for Australia to rise to third spot, held by England, in the ICC world rankings. But Clarke knows from experience how quickly he and his team can go from roosters to feather dusters.

In an interview with Fairfax Media columnist Malcolm Knox last weekend, Clarke said he feared for his job if Australia lost the Ashes again. Now he's being hailed as the hero who won them back.

But memories of recent heavy defeats in England and India keep the Australian skipper from looking beyond this series towards the next Ashes contest in 2015.

''I aim to win this Test match, probably because I've seen both sides of this game. I know how quickly you can be praised by the media, and I also know how quickly you can be criticised,'' Clarke said.

''I'm not silly enough, at 32, to look past tomorrow, because I know a couple of ducks and my job's on the line or a couple of losses and I'm under pressure. The team is exactly the same. That has been my advice to a lot of players who come onto the international scene. It's very easy to say don't look too far ahead. But it's crucial in this world, and that's where we sit as a team.

''A few months ago we were the worst Australian team to ever tour India. Ricky Ponting might have said in an article the other day this series could be the greatest-ever Ashes win by an Australian team. So things can change. I'll make sure I stay focused on this Test match.''

Clarke insists he hasn't given his longevity as captain any thought.

''Until the selectors decide to drop me, I guess, or I decide to retire,'' he said. ''Hopefully retirement comes before being dropped.

''If the team doesn't perform well then generally, in our sport, the captain's accountable and he'll probably be dropped. All I can do is continue to give my best. If somebody comes along who's better than me or my best is no longer good enough, then I'll no longer be needed here.''

The urn might be won, but individuals in the team are still striving to make sure of their positions and build confidence before the tour of South Africa.

Victorian opener Chris Rogers admits he feels under pressure as one of two batsmen, along with George Bailey, yet to score a century in the series.

But Clarke said Australia's winning form helped to alleviate the pressure on individual players.

''It always has done and it always will,'' he said. ''The more your team is winning, the more individually you're not under anywhere near as much pressure.''

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