Ponting cannot survive another defeat - Vaughan

England's former Ashes-winning captain, Michael Vaughan, believes that Ricky Ponting's reign as Australia skipper will be over if he fails to recapture the urn in the forthcoming series.

Australia's troubled build-up to the Ashes received another setback on Wednesday night, as they succumbed to a remarkable one-wicket defeat against Sri Lanka in the first ODI at Melbourne, despite having at one stage had their opponents on the ropes at 107 for 8.

Although Ponting was not involved in that match, having passed the captaincy over to Michael Clarke, the result was nevertheless their sixth consecutive defeat in all international cricket, dating back to Pakistan's victory at Headingley in the second Test back in July, and also encompassing last month's barren tour of India.

Vaughan, who has been as vocal in the build-up to this year's Ashes as he was silent ahead of the last tour in 2006-07, when injury forced him onto the sidelines during Australia's 5-0 whitewash, believes that every new set-back is a boost for England, who have been quietly building towards Friday's first warm-up match against Western Australia, having arrived in Perth over the weekend.

"Another knock of confidence," wrote Vaughan on Twitter in the aftermath of the MCG match. "Lots of people seem to be taking great pleasure from the fact Australia keep losing... long may it continue..."

Ponting was in charge during the whitewash four years ago, but his reputation was badly dented last summer, as he became the first Australian captain since Billy Murdoch in the 19th Century to lose two Ashes series in England. In Vaughan's opinion, there is no way he can stay in the job if he fails to make amends in the coming series.

"If he loses the series he will go," said Vaughan. "He has lost the Ashes twice and hasn't won an Ashes in England either. Obviously he won the 06-07 Ashes 5-0 but he had a better team to manage those days but now he has a team that is almost back in the ranks of normal cricket teams.

"His record in Australia is phenomenal but he will have to be at his best, both as a captain and as a batsman, to put England under pressure," added Vaughan. "It's harder being a captain when you don't have the ammunition in your bowling attack that includes the likes of Warne, McGrath and Gillespie.

"He doesn't have the X-factor bowlers who can change games. That puts your batsmen under a lot more pressure because they know that you have to get lots more runs to give your bowlers something to bowl at. If they'd have got 300 a few years ago, they knew that Warne and McGrath would get them back in the game, but now they need 400 plus to really put England under pressure."

Warne, for his part, hit back in the war of words when he suggested to Vaughan, via Twitter, that he shouldn't get too carried away just yet. "yeah yeah yeah, whatever bud [sic]," he wrote. "Your ( poms ) are very cocky at present , Mmmmm could end in tears for you all, just chill !"