Australia struck twice in quick succession to knock over England's big guns late on day two at the WACA Ground, with the visitors sitting on 4-180 at stumps.
First, spinner Nathan Lyon snared England skipper Alastair Cook for 72, leaving the visitors at 3-136 in reply to Australia's 385.
Then just 11 runs later Peter Siddle removed Kevin Pietersen for the 10th time in his career, the England star spectacularly caught over his head by Mitchell Johnson for 19 as he tried to break the shackles.
At stumps, Ian Bell (9no) and Ben Stokes (14no) had settled their side going into day three, still 205 runs adrift and already two down in the series.
The breakthrough came after Cook and Pietersen had been building a slow but solid partnership following the controversial dismissal of Joe Root (4).
Root was given out caught behind by umpire Marais Erasmus after it appeared Shane Watson found the outside edge of his bat.
The 22-year-old was convinced he hadn't hit the ball and while the DRS review found no hot-spot, a faint register on the Snicko was enough to send him back to the players pavilion.
The wicket was Australia's second for the session after opener Michael Carberry chopped a Ryan Harris delivery onto his stumps for 43.
Earlier, Cook and Carberry recorded their side's best opening partnership for the series, putting on 85 runs before Carberry's dismissal in response to Australia's total of 385.
Both have survived their share of half-chances on a day where the mercury has constantly flirted with the 40C mark.
The crowd was in full voice when Mitchell Johnson lined up for his first delivery in the second over, which was easily defended by Carberry.
The English opener dispatched Johnson's second delivery for four, prompting the Barmy Army to return serve to the suddenly quiet home crowd.
England's attack was on fire in the opening session, taking Australia's the final four wickets with relative ease.
James Anderson was the best of the bowlers after a tame day yesterday, finding the inside edge of day one hero Steve Smith for 111 and following it up with the wicket of Ryan Harris (12), who had looked dangerous in his short stint at the crease.
Australia resumed at 6-326 this morning and hadn't added to their total before Stuart Broad removed Mitchell Johnson for 39, breaking a handy 59-run partnership with Smith.
Broad's delivery straightened up on Johnson, finding the edge to have him caught behind in the second over of the day.
Smith was gone minutes later for 111 when Anderson found an inside edge.
Umpire Marais Erasmus called the ball not out before a score review discovered the faintest of sounds and a very slight hot-spot on the bat.
Harris was the next to go, caught by Joe Root in the gully after Anderson found the outside edge.
Nathan Lyon and Peter Siddle put on an entertaining but inelegant partnership to lift the total to 385 before Siddle nicked a Tim Bresnan delivery to wicket-keeper Matt Prior to end the innings.