Two down in the series and coming off the back of a thumping 347-run defeat at Lord's, the bookmakers make Clarke's side 4-1 outsiders to keep their slender hopes of winning the series alive in Manchester starting on Thursday.
No test cricket captain is ever likely capitulate before the toss has been made, though, and Clarke, encouraged by a tense 14-run defeat in the first test, was a model of positive mental attitude in his column in a popular Sydney newspaper.
"England were the better team at Lord's but we know we can beat them," he wrote in Daily Telegraph on Wednesday.
"This is not some sort of hollow boast. We almost won the first test at Trent Bridge little more than a fortnight ago. Big results can turn on little moments.
"We have shown enough on this tour individually to know that if we put our performances together as a unit we are a very competitive side.
"Everyone in the top seven has scored a half-century in the first two tests and our bowling has been generally strong."
Clarke assured readers the management of his long-standing back injury meant he would be able to play in the third test.
Australia are expected to recall spinner Nathan Lyon for the Old Trafford test and Clarke's comments suggested it would be at the expense of, rather than in addition to, teenager Ashton Agar.
"England have brought Monty Panesar into their 14-man squad as a second spinner, reinforcing the belief that Old Trafford can help the spinners," he added.
"However, there has already been help for the spinners from the dry pitches we have played on in the first two tests and I don't expect the conditions in Manchester to be that much different."
Clarke, who could also welcome David Warner back to the team after a period of exile in the wake of his attack on England's Joe Root in a Birmingham bar, also suggested he would bat first if he won the toss.
"They are generally good conditions for batting in the first innings and that is where we really have to cash in," he concluded.
"A good first innings allows you to control the game and gives your bowlers the chance to be more attacking, knowing there is a good buffer of runs.
"There are three tests left and we always turn up to a game believing we can win.
"Let's see what sort of history we can create over the next few weeks."
(Editing by Greg Stutchbury)
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