Andy Flower, the England coach, has not changed his view that things are "not rosy" in the Australian camp despite Ricky Ponting's side hitting back to level the series in Perth.
Australia won the third Test by 267 runs to even the five-match series at 1-1 after England had won the second Test at Adelaide by an innings and 71 runs.
England need to win only one of the last two Tests to retain The Ashes
Flower said Australia's emphatic win in Perth had not altered his belief that they are fragile and dependent on Mike Hussey and Shane Watson to score most of their runs.
"There's no doubt that everything is not rosy in their camp," Flower said. "One Test match does not create that so, yes, we realise that.
"Watson and Hussey have been very good for them so far and we will be looking to make the most of that in this next Test [in Melbourne]."
Flower acknowledged concerns that England were asking too much of their bowlers by persisting with a three-pronged seam attack through the series,
England used James Anderson, Chris Tremlett and Steve Finn in Perth, and the lack of a fourth pace bowler did appear to hurt them as they allowed Australia to recover from poor starts in both innings.
They had been 69 for five in the first innings before reaching 268, and then were wobbling at 64 for three in their second innings before moving to 309.
"A five-Test series is hard on everyone, both physically and emotionally. For the fast bowlers even more so, I would say," Flower said.
"The workload on our bowlers is heavy. In the absence of a quality all-rounder we're sticking with our four-bowler attack and we've shown over the last 18 months that it's served us well."
Flower would not refute suggestions that Ian Bell may be promoted in the batting order to allow Kevin Pietersen and the struggling Paul Collingwood to bat lower, shielded to an extent from the Australian fast bowlers.
"We are always looking at ways to improve our side," Flower said. "Ian Bell looks in very good form, he's very confident and he's played beautifully throughout this tour.
"Jiggling with batting orders and personnel is always an option but you also have to be careful about altering a side that's been very successful over the last 18 months."