Kevin Pietersen was in bullish mood after launching his Ashes tour with a confident 58 against Western Australia and feels "on fire" after his short stint in South Africa ahead of travelling to Australia.

Pietersen's form was the biggest boost to come out of the second day at the WACA but the rest of England's top order struggled as they visitors slipped to 8 for 159 before Stuart Broad and Graeme Swann clubbed a face-saving partnership. Pietersen hasn't scored an international hundred since March 2009, against West Indies in Trinidad, and even though England have been successful during his lean run many feel he has to perform for them to retain the Ashes.

Pietersen, given a life in the slips on 25, drove strongly through the off side and used his feet to loft Michael Beer, the left-arm spinner, down the ground before miscuing a drive to gully off Michael Hogan and he said his confidence is now coming flooding back.

"I have never really been a technical player, you've seen me play for six years," he said. "I play like a clown, it is my mental approach that I needed to change. I needed to get a load of confidence back and I'm on fire at the moment, so I am very happy."

"I really enjoyed today, it is always nice to get time out in the middle," Pietersen added. "I have been working really hard over the last six weeks to get to a place where I am at at the moment. As I said, coming back from South Africa a couple of weeks I feel top draw again."

This was his first innings for England since making a first-ball duck in the final Test against Pakistan, at Lord's, in August. He was omitted for the Twenty20 and one-day series which and signed a loan deal with Surrey before organising his own trip to the Natal Dolphins in a quest to regain his form by linking up with one of his mentors, Graham Ford.

"It was amazing, I have worked with him since I was six or seven years old and he is a great family friend," he said. "Fordy just knows me. He knows how to sort me out."

Pietersen insisted that he hasn't taken any notice of Australia's problems in recent days as they slumped to a series defeat against Sri Lanka amid talk of disquiet in the team.

"I haven't watched a single ball," he said. "My computer is turned on to Skype, and I speak to my wife and my baby as much as I can. I haven't even turned my television on in Australia; I haven't read a headline, nothing. Somebody told me this morning that they lost, but that's got nothing to do with us."