Lifeless and zapped of energy, England lost two wickets before tea as Australia closed in on another comprehensive Ashes victory following their large declaration in the fifth Test.
England watched helplessly as Australia reached 649-7 - a lead of 303 thanks to memorable centuries from brothers Shaun and Mitchell Marsh - before Steve Smith declared in sweltering conditions at the SCG.
With the temperature exceeding 41 degrees Celsius in Sydney - staggeringly 56 out in the middle at one stage - and having already surrendered the urn to Australia, England crumbled in the middle - openers Alastair Cook (10) and Mark Stoneman (0) dismissed quickly by star duo Mitchell Starc and Nathan Lyon to leave the embattled tourists 25-2, a deficit of 278 runs.
It was the Marsh show early on Sunday - Shaun and Mitchell both raising their bats after scoring hundreds in the same innings to lead the Aussies to 578-5 at lunch and 232 runs ahead.
Shaun Marsh added 15 runs to his score post-lunch before he was run out by Stoneman for 156.
Starc (11) came out swinging and he was sent back to the pavilion in the same way as he tried to smash Moeen Ali (2-170) for six, caught easily by James Vince.
649 - Australia have posted their third highest innings score ever in an #Ashes Test on home soil.-- OptaJason (@OptaJason) January 7, 2018
9/662d at Perth in Dec 2017
8/659d at Sydney in Dec 1946
7/649d at Sydney in Jan 2018
Tim Paine (38 not out) and Pat Cummins (24 not out) added more invaluable runs as Australia posted their third highest innings score in an Ashes.
Sent in to bat again having bowled 193 overs in boiling conditions, England never looked comfortable and it was not long before star paceman Starc (1-10) trapped Stoneman lbw for a duck, despite a review.
After become just the sixth player bring up his 12,000th Test run, Cook was then bowled by a stunning delivery from in-form spinner Lyon (1-2). This came after he was spared a life, when he was dropped by Shaun Marsh at first slip.
Arriving with England 15-2 and in serious trouble, captain Joe Root (8 not out) managed to steady the ship and lift the intensity alongside Vince (6 not out).