England know they must play equally as well in Sydney as they did in Melbourne if they are to win the Ashes outright this winter.

An innings-and-157-run trouncing of Australia at the MCG means Andrew Strauss' tourists have retained the urn with an unassailable 2-1 lead and head for the final Test at the SCG on the verge of history as the first England team to win a series down under since 1986/87.

In a seesaw battle so far, however, that is no formality against hosts minus injured captain Ricky Ponting for this last match - starting on Monday - but who themselves inflicted a wide-margin defeat on England well inside four days in Perth.

England's off-spinner Graeme Swann, who finished 2010 as the world's leading wicket-taker in that calendar year, is certainly well aware only another outstanding effort will be properly rewarded.

"We still face a formidable opponent, probably smarting from the last game - we're not taking anything for granted," he said.

"We've played exceptional cricket in the last game and we're going to have to do so again."