England were on the verge of retaining the Ashes after feeble Australian batting left the fourth Melbourne Test at their mercy on Tuesday.
The tourists left the Australians with the huge task of either scoring 415 runs to make England bat again or lasting out eight sessions to secure a draw but the home team showed little fight after their opponents had amassed 513 at the MCG.
Australia were facing probable defeat some time on Wednesday's fourth day with no rain forecast over the last two scheduled days of the match.
At the close, Australia were trailing England by 246 runs at 169 for six with Brad Haddin on 11 and Mitchell Johnson on six.
Yorkshire seamer Tim Bresnan prised open the Australian top order in a mesmerising spell of 3-22 off 14 overs to trigger the slide.
Ricky Ponting's grim struggle for runs ended after 101 minutes when he was bowled by Bresnan for 20.
The Australian skipper got an inside edge onto his stumps to continue a wretched series, having now scored just 113 runs at 16.14 and putting his distinguished 152-Test career in peril ahead of next week's final Test in Sydney.
It has been a fraught match for Ponting. He lost a crucial toss, his side were routed for a first-day 98, he was fined and censured by the match referee for a prolonged argument with the umpires over a disputed referral, and the runs have dried up.
Australia's hopes of saving the Melbourne Test plunged with Ponting's exit and it got worse when their series leading scorer Mike Hussey perished for a duck in Bresnan's next over, snapped up by Ian Bell at short extra cover.
Vice-captain Michael Clarke capped a poor series when he fell to spinner Graeme Swann for 13, playing forward and edging to Andrew Strauss.
Young Steven Smith resisted for 91 minutes before he attempted a pull and was bowled by James Anderson for 38.
Shane Watson, who ran out his opening partner Phillip Hughes, yet again failed to build on a half-century and was out lbw for 54 after not offering a shot to Bresnan.
Watson has passed 50 a total of 17 times in Tests, but only converted two of them into centuries.
Hughes, fighting for his Test career, was the victim of a poorly-judged run by batting partner Watson.
The openers had comfortably taken the score to 53 but inexplicably Watson scurried off for a risky single to cover only for Jonathan Trott to swoop in and effect the run out.
Hughes looked a disconsolate figure as he trudged from the ground after scoring 23 off 30 balls.
Watson has been involved in six run outs in 26 Test innings and has been run out just once.
England were dismissed at lunch with Trott remaining unbeaten on 168 as the team's marathon innings, stretching over 700 minutes and 159.1 overs, finally came to an end.
Trott batted for 468 minutes, faced 345 balls and hit 13 fours in an innings that fortified England's impregnable position.
England, resuming at 444 for five, lost their remaining five wickets in the morning session.
Matt Prior, who was caught off a no-ball when he was on five, chipped a catch to Ponting at mid-on off Peter Siddle for 85.
Siddle then had Bresnan caught behind for four and Ben Hilfenhaus picked up his first wicket with Swann caught behind for 22.
Hilfenhaus bowled Chris Tremlett for four and Siddle wrapped up a big-hearted bowling performance with the wicket of Anderson for one.
Siddle finished with 6-75 off 33.1 overs but Australia lost paceman Ryan Harris with an ankle stress fracture while bowling in the morning session.
Australia will now need to find a bowling replacement for Harris for the Sydney Test.