Kevin Pietersen believes England's disappointing start to the Ashes series underlines Australia's strength and highlights just how impressive last year's victory over them was.

Victories in Brisbane and Adelaide have put Australia in pole position to reclaim the Ashes, a target they could achieve with another win in this week's third Test at the WACA.

England's struggles have attracted scorn and criticism, particularly their dramatic slide to defeat on the final day at the Adelaide Oval, and have prompted comparisons with the dark days of one-sided Ashes campaigns.

But Pietersen believes England have not been given enough credit for their memorable Ashes triumph on home soil, and has found plenty of room for optimism in the manner they played for the first four days in Adelaide.

''I've always said that I don't think people realise how good it was to beat Australia in England,'' claimed Pietersen.

''Everyone thought we'd come out here and it was going to be level-pegging but you get a champion in a corner and he'll come back at you.

''These blokes are a champion team, probably the best Australian team they've ever had, and they've come back doubly hard.

''Adelaide was fantastic for us for those first four days and we played magnificent cricket against this side in testing conditions.''

Having battled so hard for the opening four days, however, England's capitulation to Shane Warne on the final morning sealed their fate and enabled Australia to claim a six-wicket triumph.

''It was just two hours and if we can put that behind us, which I think we have done looking at the way we've gone about this week, if we put in five good days then we can spin a good result for us and the series,'' he insisted.

''We played a bad couple of hours but that's life and you've just got to get on with it. There's an opportunity for us to turn the series around and that's what we have to do.''

One of the biggest challenges since transferring from Adelaide to Perth has been to lift themselves both individually and as a unit to challenge Australia again this week.

Captain Andrew Flintoff admitted a desperate sense of dejection immediately after the defeat and even Pietersen, normally one of the most positive members of the squad, has struggled to come to terms with the events.

He admitted: ''It was really difficult. I'm a really positive bloke and it was hard. I was in my bedroom that night thinking about how the heck that could happen?

''I wondered whether I was dreaming, was it for real and all that kind of stuff. At the end of the day it is one of those little wars lost and it's a case now of going out and being as positive as we can.

''Our training session today showed we mean business.

"We know that this is a huge, huge week for us and we definitely don't want to be here next week talking about being 3-0 down in the series.

''We know what we've got to do this week and it's crunch time. The boys have been put through their paces massively today and from the first ball that was bowled in the nets it was 90mph-plus.

''We'll be going out with all guns blazing knowing we've got to play positive cricket and we've got to win this Test match.''

Once again the key duel in the middle will be between Hampshire team-mates Pietersen and Shane Warne, who needs only six more victims to become the first bowler to claim 700 Test victims.

Pietersen received many messages during the 2005 series from Warne informing him he had been targeted as his 600th victim - a dubious honour which Marcus Trescothick claimed - but is yet to be greeted by similar banter.

He has been more successful than just about anyone in world cricket apart from Brian Lara at handling Warne, with the obvious exception of being bowled around his legs attempting a sweep in the second innings at Adelaide.

But Pietersen intends to relish another opportunity to battle with Warne, claiming: ''I've always enjoyed facing Shane and I'll enjoy facing him this week but hopefully it will last a lot longer than one ball.

''From my point of view, it's just a bowler running in to bowl at me and I've got to score runs. It's my living scoring runs and his is taking wickets.

''I don't worry about who is bowling. It's important to keep things as simple as you can - you've got to concentrate on just the ball.''

England are yet to formulate their starting line-up, but Monty Panesar is heavily tipped to replace fellow left-arm spinner Ashley Giles after sitting out the opening two Tests