"The one person England have to have is Kevin Pietersen. If England haven`t got Pietersen I don`t believe they can win. He`s just a wonderful player," Warne said about his former Hampshire teammate.
Australians have been outspoken that they dread Pietersen, who has scored 963 runs at 53.50 in 10 Ashes matches, was the only hurdle in their way to Ashes.
But the right-handed batsman can miss the traditional five-Test series beginning July 8 in Cardiff, owing to Achilles tendon injury.
"England haven`t rushed Rashid and I think he`s played pretty well in his limited opportunity in (the World) Twenty20," Warne said.
"He should play in the first Test with Graeme Swann. Rashid and Graeme Swann; Ryan Sidebottom and James Anderson - that`s a really well-balanced attack for the conditions you`re going to have over here."