'Ashes will be tough but that's not to say England can't beat Australia'

England captain Alastair Cook (second right) and teammates chat during England nets ahead of the first Ashes Test match against Australia in Cardiff. Photograph: Stu Forster/Getty Images

Former captain Kevin Pietersen believes the form of three players will be key to England's hopes of beating Australia to regain the Ashes in their Test series starting in Cardiff on Wednesday.

The controversial batsman, who was sacked by England last year and denied a recall, told online sports bookmaker Paddy Power on Monday that, contrary to widespread expectation, England can win the series.

"This is going to be a very tough series. Ashes series always are, but that's not to say we can't beat Australia. Far from it, in fact.

"However, a great deal relies on the form of three players Australia will be most concerned about -- Joe Root, Jimmy Anderson and Alastair Cook," Pietersen said.

'Root has transformed into a proven match winner'

England player Joe Root raises a smile during England nets ahead of the first Ashes Test in Cardiff. Photograph: Stu Forster/Getty Images

Pietersen was cast aside by England after two stormy years of troubled relationships with the management and his team-mates following the 2013-14 Ashes series in Australia.

England lost all five Tests, four out of five One Day Internationals and all three T20 matches.

The South African-born right-hander said Root, who shone in England's much-improved Test and one-day displays against New Zealand in May and June, is crucial to England’s hopes.

"In Joe Root, we have one of the most exciting and in-form players in the world right now," he explained.

"Last time Root played in an Ashes series, he was a young guy, new to the team, but now he's very much an established international player and someone we’ll look upon to bring the attack to the Aussies.

"Over the last year or so, we've seen him transform from a young man with vast potential to a proven match winner and his form will be vital if we're going to reclaim the urn."

'Cooky will need to be at his best'

Kevin Pietersen speaks with England captain Alastair Cook. Photograph: Getty Images

Pietersen also had positive words about Cook, the captain who played a role in his removal from the England squad.

"Cooky will need to be at his best as well if we are to stand any chance," he said.

"We've seen over the years, and importantly so this summer, just what a fantastic batsman he is and, if he can make a big score in Cardiff, the Aussies will certainly have cause for concern.

"An in-form Cook, batting over a great deal of time, is something Australia will be extremely fearful of."