Cummins running hot at the Gabba
PAT Cummins took his fourth wicket of Sri Lanka's second innings with another stunning delivery.
Roshen Silva caught the outside edge, giving Joe Burns his second catch of the day.
It dropped Sri Lanka to 4-35, still 144 runs away from making Australia bat again.
"That's the knockout blow," Michael Vaughan called on Fox Cricket.
"Push the batsman back, press him onto the back foot and throw it fuller to entice the drive, outstanding from Cummins."
Brett Lee added: "And outstanding work from Tim Paine to keep him on for one more
"He's kept him on for that last killer blow and he's got it."
After seven overs, Cummins had 4-9 with five maidens.
He struck with the last ball on Friday night, getting Dimuth Karunaratne caught behind and sending the Aussies to the sheds with their tails up.
And on Saturday, just in case the side needed another hype up, Cummins struck with his second ball.
The big seamer was thrown the ball after Jhye Richardson bowled the first over.
Cummin's ball looked to surprise Sri Lankan skipper Dinesh Chandimal, catching a high edge and ballooning to Kurtis Patterson at gully.
Cummins then had Test cricket's second-leading run-scorer of 2018, Kusal Mendis, nicking to Joe Burns at second slip.
"Pat Cummins, he's in the middle of a hot streak here for Australia," Fox Cricket commentator Mike Hussey said.
"Sri Lanka in big trouble here now."
With 3-0 off his first 13 balls, Sri Lanka finally hit him for runs with a three to pass the 20 mark.
Shane Warne, a vocal critic of Mitchell Starc this summer, said it was good to see Cummins start with the ball in hand.