Ben Stokes struck twice before lunch to help give England four wickets to show for their gamble to bowl first under cloud cover in the final Test.
Stuart Broad quickly eliminated the prolific David Warner; then first-change Stokes doubled up with Chris Rogers and Australia captain Michael Clarke, before Shane Watson fell to James Anderson from the final ball of a hectic session in a total of 94 for four.
As England try to somehow avoid a series whitewash at the SCG, they picked three debutants here - for the first time in almost eight years - Gary Ballance, Boyd Rankin and Scott Borthwick respectively coming in for Joe Root, Tim Bresnan and Monty Panesar.
Alastair Cook then won his first toss of the winter, and decided to try to take advantage of a green-tinged pitch before the Sydney sun got to work.
Broad was threatening wickets from the outset, while Anderson bowled a more conservative length with the new ball from the Paddington End.
Warner had just taken three fours from Broad's previous over, and passed 500 runs for the series, when he paid little respect to a decent delivery which beat a flaky shot and hit the top of off-stump.
Rogers also picked the wrong length against Stokes, when he under-edged a pull via his pads on to the base of leg-stump.
England predictably switched straight back to Broad to attack Clarke with the short ball.
Since Clarke compliantly and haplessly gloved Broad to short-leg in his first innings of the series at the Gabba, he has barely looked susceptible at all.
But Stokes did get him with one that kicked from just short of a good length to have him edging to Ian Bell at second slip.
Counter-attacking number three Watson had got under way by driving his first delivery from Broad through extra-cover for four, and soon clicked into similar mode against Stokes.
Rankin's first four-over spell in Test cricket proved encouraging but fruitless as he hurried and worried Watson in particular with his bounce yet mixed in one or two easy scoring opportunities too.
It was to be Anderson instead who returned to have Watson lbw, playing round his front pad, an echo of last summer - back when England had Australia just where they wanted them.