Australia took a major step towards regaining the Ashes after powering into a commanding first innings lead in the third Test thanks to Steven Smith's second double century as England toiled on day three in Perth.
Captain Smith struck his highest score in the longest form of the game and second three-figure effort of the series, reaching the close on 229 not out, putting on a mammoth 301 for the fifth wicket with the returning Mitchell Marsh.
All-rounder Marsh [181 not out] piled on the pain for England with a blistering maiden century as Australia went beyond England's first innings 403 - which looks even more under par than it had appeared when they were skittled out on day two - and built a handsome lead.
England had begun the day 200 runs ahead but few could have predicted what would follow as their advantage evaporated.
They did make one breakthrough early on as Moeen Ali snared Shaun Marsh for 28 but that was the only positive from a day which saw the urn further removed from their grasp.
Smith was at his calm, serene best to do justice to his status as the number one batsman in the ICC Test rankings and a triple century surely beckons. But at the other end Marsh was utterly destructive smashing 29 boundaries in the day alone and taking apart England's attack.
Stuart Broad, Chris Woakes, Craig Overton and Ali all went for centuries with the ball while James Anderson was ineffective on a surface which while still good for batting also exposed the tourists' alarming lack of pace.
Though perhaps most demoralising for Joe Root will be the lack of opportunities created by the quintet, after three opportunities had gone down on day two, and it leaves their hopes of taking the series into the Boxing Day Test in Melbourne in tatters.
When play finally came to an end Australia finished on 549 for 5, a lead of 146, and with Smith and Marsh unbeaten at the crease the hosts will look to increase their advantage on day four before forcing England to save a match which looks destined to signal the end of their Ashes reign.