Sydney: England all-rounder Paul Collingwood is impressed by Michael Clarke for keeping his batting intact despite the pressure of captaincy but is not threatened by Australia's resurgence.

England had defeated Australia 3-1 in the away Ashes series this year and then climbed to the top of the Test rankings after whitewashing India 4-0 at home.

Australia are in the process of re-building the team after the retirement of several key players such as Glenn McGrath, Shane Warne and Matthew Hayden.

However, the young Australian side has managed to dominate a star-studded India so far in the four-match series. But Collingwood refused to read too much into Australia's performance and said only the next Ashes will tell where the Aussies stand.

"The captaincy tends to suffocate many players but that doesn't seem to have happened with Michael Clarke," the former England captain said in praise of the Australian skipper, who smashed an unbeaten 329 in Sydney Test on Thursday.

"It's an unbelievable effort to get more than 300. It's very hard to know where teams are at. India in India are a very different proposition than away from home and we'll only find out at the next Ashes how far teams have come," Collingwood said.

The next Ashes series will be played in England in 2013.