And with the in-form Ian Bell padded up to come in next, Australia's task won't get any easier as the afternoon progresses. By lunch, England were 3 for 449, having added 132 to their overnight total, with Pietersen in vintage touch on 158 - the same score he made in the Adelaide Test of 2006 - and Collingwood on 40, on another hot and exhausting day of 30-degree weather in Adelaide.
Australia's only cause for celebration came when Cook, on 148, feathered a thin inside edge off Ryan Harris to Brad Haddin, who hurled himself to his right to take an athletic catch. Cook's dismissal left him on 450 runs from his three innings so far this series, more than any Australian batsman managed throughout the entire 2009 Ashes campaign.
It was a well-deserved wicket for Harris, who was easily the best of Australia's bowlers, although he didn't have much competition in an attack that struggled for impact. But any bowling attack around the world would have trouble containing Pietersen in the sort of mood he has displayed during this Test.
For Australian fans, seeing Pietersen in this touch, it is impossible to believe he had not scored a Test hundred since the tour of the West Indies in March 2009. He was forceful through the off side, driving hard and finding gaps, and regularly walked at the fast men to thump deliveries through midwicket with disdain.
His century, which came with a clip off his hips from his 158th delivery, brought a screeching roar from Pietersen that would have fitted into a horror movie, which was pretty much how the Australians were viewing the Test. By lunch, he'd also passed 150, and with eight sessions remaining in the Test, who knows what sort of score Pietersen will end up with.
Adding to Australia's problems, the left-arm spinner Xavier Doherty was providing little threat to any of the right-handers, but the right-arm offspinner Marcus North spun a few sharply out of the footmarks. That means that in whatever fightback Australia's batsmen can muster in the second innings, they'll have to counter a dangerous Graeme Swann.
