England need a monumental effort, but still have the hunger for a scrap to retain the Ashes, captain Alastair Cook says.

Humiliated in consecutive Tests, England travel to Perth for the third Test starting on Friday knowing if they lose again, they lose the Ashes.

“A lot of people … will probably give us no chance,” Cook told reporters on Monday after England’s 218-run loss in the second Test in Adelaide.

“But if we believe that the urn is gone, then it might as well have gone.

“Two-nil (down) is obviously not a great situation to be in. But if you look at football games, the next goal can change it very quickly … but it’s going to take a monumental effort from us to do it.”

Cook denied England, after three consecutive Ashes series wins, had lost their competitive hunger.

“When you haven’t been playing well, that is one thing you start looking at, whether we do have that (hunger),” he said.

“I can only say from speaking to the guys and watching how much this is hurting, that we do.

“Only the guys will know that inside themselves but I honestly believe we have got that.”

Cook also defended star batsman Kevin Pietersen from claims he was lacking motivation.

“He’s a senior player and he’ll be the first to hold his hand up and say some of his shot execution and selection hasn’t been good enough,” Cook said.

Cook himself has struggled, averaging 33.74 this series and 36.39 in the winter Ashes – returns a far cry from his average of 127 on England’s 2010/11 Ashes tour of Australia.

“I need to score more runs, it’s a simple deal,” he said.

“There is only so many times you can keep telling the lads to do it, and if you’re not delivering, it makes it harder.

“There are some very tough moments for the captain and we’re in the middle of it … it does hit you hard.

“But we’re the only guys who can turn it around and obviously I’ve got to play a big part in that as the leader.”