Australia are primed to pounce with the second new ball on Friday after England paid the price for not employing a nightwatchman in a dramatic finale to the first day of the fifth Ashes Test.
Steve Smith's men seized the momentum by landing two huge blows in the last two overs at the SCG, denying England captain Joe Root an elusive century in this series in the process.
The tourists had appeared on track for a sizeable first-innings total with Root (83) and Dawid Malan (55 not out) enjoying a healthy fourth-wicket partnership.
But the England skipper's hard work was undone in the penultimate over of the day, and the first with the new ball, when he flicked a half-volley square to a waiting Mitchell Marsh.
The bowler was Mitchell Starc, who had on Thursday been the subject of discussion about his fitness after his speed dropped off alarmingly.
There didn't appear to be too much of an issue with the heel that led him to miss the Boxing Day Test at the close, however, as the left-arm spearhead and teammates celebrated Root's exit.
They were given a further boost when Josh Hazlewood finished the day in style, finding the edge of new batsman Jonny Bairstow.
England will resume on Friday at 5-233, their ambitions of completing a highly competitive first-innings score and salvaging something from this series suddenly looking in question.
The fact that that Bairstow was sent in after Root's dismissal rather than a nightwatchman cost them dearly, with the decision leaving players on both sides scratching their heads. "I was very surprised," Mitchell Marsh said. "I would have had the nighty."
Malan, who England now need to press on and make a second ton of the series, was also not expecting to see Bairstow walk out with only minutes left in the day's play.
"I was a little bit [surprised] but the decision is not the coach's to make, that's down to the batsman who is next. Jonny made the decision and good on him for making it it takes a lot of guts to go against what people normally do," Malan said.
"Some people like it and some people don't. I'll have a nightwatchman every time. Each to their own. You can't really look back. He backed himself and he got out."
Led by Hazlewood and Pat Cummins, Australia's bowlers battled away after a rain-affected start to the day and earned the two prizes at the death. England, having surrendered their advantage, may now have to contend with a revitalised Starc as well on the second morning after he woke from his slumber to make the major breakthrough.
"It was great to get the late reward as a bowling group for our toil," Mitchell Marsh said.
"Two three-hour sessions took it out of us. To get those last two chances was great for our confidence. We've got a two-over-old ball tomorrow and hopefully we can get stuck into it tomorrow."
For England it was the same old story. "I think it sort of sums up where we've been in this tour," Malan said. "We've been on top for so long in games and we make one or two mistakes and let the Aussies back in.
"It is disappointing. Rooty played fantastically well to get to that position. To be five down now after the hard work we put in today is obviously not ideal."
While Marsh's sharp catch saw Root on his way Australia had not done themselves any favours earlier in the field by missing a runout and Steve Smith spilled a low chance at slip.
