Hobart: Australia captain Michael Clarke pledged no mercy on Scotland, as the four-time World Cup champions seek a headline-grabbing performance ahead of a potential quarter-final collision with Pakistan.

Australia have already made sure of their spot in the next stage after last weekend's 64-run win over fellow title contenders Sri Lanka, where they piled up 376 for nine.

That followed their World Cup record score of 417 for six to rout Afghanistan by 275 runs.

Victory against Pool A's rock-bottom Scotland on Saturday will ensure the runners-up spot behind New Zealand and a possible last-eight clash in Adelaide on March 20 against old adversaries Pakistan should Misbah-ul-Haq's side beat Ireland on Sunday.

'It doesn't matter who we're playing against. There will be no mercy for any opponent. Everybody has turned up to train, wanting to get better,' said Clarke.

'We need momentum, and we need to grab it and run with it for as long as we possibly can. In Hobart, it'll be full steam ahead looking to become better individually and as a team.'

The only selection issue appears to still revolve around Shane Watson who was dropped for the Afghanistan match but restored to the line-up for the win over Sri Lanka in Sydney. He certainly responded with a fine innings of 67.

'The way Shane played the other day was fantastic. I think he sort of adopted that approach where he knew he could come in and play his game,' said opening batsman David Warner.

'As he was out of form, he probably had the luxury to go in and play the way he wanted to play and that's the message he probably wanted to send to everyone: he can still play this form of the game, it doesn't matter where.

'With the team we've got and the balance we've got, we showed the other night with the bat what can happen.'

Clarke also shrugged off fears over his fitness, claiming he was more concerned about the time in the middle.

'I certainly am fit,' Clarke insisted. 'It was more just part of my recovery. Since coming back from my hamstring surgery we've looked at my schedule going forward and Thursday was another opportunity to make sure I recover as well as I can, not only for this game but for the quarter final.'

With Australia already assured of a place in the quarters, Clarke said he may opt to juggle the batting order to allow more players time in the middle on Saturday.

'I think the order will be a little bit different to try and give guys a hit ahead of our quarter-final,' Clarke said.

Along with Shane Watson and James Faulkner, Clarke said he needed to spend some more time at the crease.

Fast bowler Pat Cummins will replace spinner Xavier Doherty for Saturday's match.

Doherty played in the 64-run victory over Sri Lanka at the Sydney Cricket Ground but went wicketless in seven overs, conceding 60 runs on a pitch generally sympathetic to spinners.

Now Cummins, who played in the one-wicket defeat to New Zealand in Auckland two weeks ago, gets a second chance to make an impression at the Bellerive Oval ahead of a March 20 quarter-final date against Pakistan or Ireland in Adelaide.

'I like the fact the selectors are picking players for conditions and opposition,' Clarke said on Friday. 'I think we'd be silly to pick our team today for the World Cup quarter-final.

'We don't know what we're going to get in Adelaide, we don't know what the wicket will be like, we still don't know who we will be playing against. I think we will assess that next week or in a few days.'

Australia will have little to fear from a Scotland side who have still to win a World Cup match in three appearances.

The two sides have met four times with Australia winning by six wickets in 1999, 203 runs in 2007, 189 runs in 2005 and 200 runs in 2013.

In that last match in Edinburgh, Australia motored to 362 for three based on an opening partnership of 246 between Aaron Finch (148) and Shaun Marsh (151).

Finch will be optimistic of a similar carnage on Saturday on the Bellerive Oval's compact boundaries although Scotland would have breathed a sigh of relief when Marsh wasn't selected. (AFP)