David Warner put Australia into prime position to reclaim the Ashes in the third test, making England pay dearly for its missed opportunities as he helped increase the lead to 369 runs with a rapid century yesterday.
Warner clubbed 12 boundaries and two sixes at the WACA, surviving stumping opportunities on 13 and 89, and shared a 157-run opening stand with Chris Rogers (54) before lofting Graeme Swann to Ben Stokes at long-on, out for 112.
The England attack sorely missed leading paceman Stuart Broad, who went for scans after being hit on the right foot as he was trapped lbw by Mitchell Johnson in the morning session, and didn't return to the field.
At stumps on day three, the Australians were 235-3. After big wins in the first two tests, they now overwhelming favourites to clinch the five-match series in Perth.
Momentum on the middle day was with the Australians from the third over when they challenged a not-out decision for lbw against Ian Bell (15) and got it overturned.
England vice-captain Matt Prior's day started badly with his irresponsible dismissal and got worse when he missed two stumping chances against Warner and left a difficult chance from Rogers to Cook at first slip.
England resumed at 180-4 and added only 71 in 20 overs before Peter Siddle (3-36) finished them off on the stroke of lunch, giving Australia a 134-run first-innings buffer.
Ryan Harris (3-48) struck an early blow when he hit Bell on the knee with the total at 190. Umpire Marais Erasmus' not out decision was overruled with tracking technology.
England passed 200 for only the second time in the series before Prior (8) bottom-edged a simple catch to Brad Haddin.
Warner and Rogers had no real difficulty against the weakened attack and produced the biggest opening stand of the series. It ended after tea when Rogers played a loose shot to a wide ball from Tim Bresnan and cut straight to Michael Carberry.
Watson had a chance on eight, attempting a quick single, when Carberry missed a throw at the non-striker's end that would have run him out. He had another let-off on nine when he tried to sweep Swann and paddled a difficult chance to Ian Bell, who couldn't hold it.