Matt Prior knows from his own chastening experience that England must blank out premature congratulations for Ashes success.
Captain Andrew Strauss and coach Andy Flower have both been at pains to stress England have so far won just one and drawn another of their five Tests against Australia this winter.
The cheerleaders are already pointing out that a second victory in Perth next week will mean England have retained the Ashes before Christmas.
That, though, is dangerous talk - according to their wicketkeeper.
"You've got to be careful you don't fall into the trap of too much back-patting too early," he said, as he prepared to play as a specialist batsman - Steve Davies will be behind the stumps - in the three-day match against Victoria, starting at the MCG tomorrow.
"We've played well; the tour's gone well so far - but that's all in the past now.
"We're 1-0 up. That's fantastic. We've got to make sure we go 2-0 up."
It is only 16 months ago that England went to Headingley in the 2009 Ashes, with similar positive vibes ringing in their ears.
But on the morning of the fourth Test, there was a shriller sound when they were awoken at 4.30am by a fire alarm at the team hotel.
Prior then succumbed to a back spasm just before start of play - and although it did not stop him batting, England were bowled out cheaply on the way to an innings defeat inside three days.
They recovered to famously clinch the Ashes at the Brit Oval two weeks later.
But Prior has not forgotten what happened in Leeds. "You can fall into a trap if you start looking too far ahead," he warned.
"Certainly in 2009 during that Ashes, the one game we probably looked too far ahead was that Headingley match.
"We suddenly found ourselves 102 all out - and it was game over.
"We've learnt our lesson from that.
"In the past we've played good cricket and in the very next game played pretty poor cricket.
"If you want to win big series you have to play consistently ... and never take your foot off the gas.
"You can't have one great game and one poor game."
Flower is confident England will not get swept away on a tide of complacent expectations.
But Prior added: "That's why the danger would be 'oh, we're 1-0 up, we can win the Ashes'.
"All these comments start flooding in, and it's tempting to start thinking like that. But you have to guard against it."
None of the above takes the gloss of England's second-Test innings victory at the Adelaide Oval - where, like Flower, Prior believes England approached perfection.
"It was probably the proudest moment for me on a cricket pitch, that
last day in Adelaide.
"It was pretty much the perfect game. But as Andy said, it counts for nothing if we go into the next game and throw away the lead we have."
Australia appear to have been thrown into a state of confusion by their weak finish to the drawn first Test, and then their miserable performance in Adelaide.
There has even been a fanciful tide of public opinion behind an improbable comeback by Shane Warne, almost four years after his retirement and at the age of 41.
The home squad for the WACA is due to be announced tomorrow - and even without Warne, there could be several changes.
England have been careful to avoid comment on the opposition all tour.
But Prior said: "If you're chopping and changing a lot, people can play for their individual spots instead of playing for the team."
England will have to make just one alteration to their winning side, thanks to Stuart Broad's stomach injury.
Flower has hinted he already knows which of Chris Tremlett, Ajmal Shahzad and Tim Bresnan will replace Broad in Perth - and the informed consensus is it will be the tall Surrey seamer, on a pitch still renowned for extra bounce.
All three will have their chance to impress over the next three days, though, as England rest their established frontline attack.
Prior believes any one of them will do England proud.
Comparing Tremlett and Broad, he said: "There are obvious likenesses, mainly the height and bounce they get.
"But any one of our guys coming into the team is more than capable of playing that role and doing a very, very good job for England.
"They all bring different attributes and different skills.
"Whoever comes into that XI, we back 100% - and I'm sure he'll do very, very well.
"They all bowl a very heavy ball and on their day can be very quick.
"Tremlett, with his height and bounce, can be very, very awkward at times. When he gets it right he's very hard work.
"Ajmal, with the areas he hits, he's always asking questions of the batsmen. He's very good with reverse swing."
England, v Victoria at the MCG, starting at 11am tomorrow (midnight tonight GMT), from: AJ Strauss (captain), AN Cook, IR Bell, EJG Morgan, MJ Prior, PD Collingwood, SM Davies (wkt), TT Bresnan, A Shahzad, CT Tremlett, MS Panesar, IJL Trott