A dazed England lost four wickets in a hostile late spell to leave them at 31-4 -- still trailing Australia by 51 runs -- and fighting to save their Ashes hopes after day two of a gripping third Test.
It came after the visitors -- who must win in Melbourne -- were rocked by four positive Covid cases in their camp, although no players were among them.
Marcus Harris top-scored with a battling 76 against a dangerous English attack led by veteran Jimmy Anderson, who was at his fearsome best with 4-33 off 23 overs. After heavy defeats in Brisbane and Adelaide, England must win to keep the five-Test series alive, with Australia only needing a draw to retain the urn as holders.
But faced with surviving the final hour against a revved-up Mitchell Starc and Pat Cummins, England collapsed again. Struggling opener Zak Crawley never looked comfortable and after dodging 15 balls he was caught by wicketkeeper Alex Carey for five off Starc.
Dawid Malan came in but incredibly was out first ball to Starc lbw after an unsuccessful review, then Scott Boland ruined Haseeb Hameed's day on seven, with Carey gloving an edge.
England earlier took their chances with the key wickets of Marnus Labuschagne (1) and Steve Smith (16), along with nightwatchman Nathan Lyon, before lunch.