Pakistan 194 for 6 (Shafique 62, Masood 54, Cummins 3-37) trail Australia 318 (Labuschagne 63, Jamal 3-64) by 124 runs
Captain Pat Cummins clean bowled Babar Azam with a gem of a delivery during a spectacular spell late on day two to trigger a Pakistan collapse as Australia gained control of the Boxing Day Test.
With the MCG surface seemingly flattening in sunny conditions, Pakistan had moved confidently to 124 for 1 before Cummins took over with three wickets as Australia look set for a valuable lead on the first innings.
It was a disappointment for Pakistan having mustered a resolute performance for much of the day. After dismissing Australia for 318 by lunch, Pakistan responded well with opener Abdullah Shafique and captain Shan Masood building a 90-run partnership as they scored briskly after tea.
Having batted watchfully through the second session, Shafique put the foot down with several superb strokes square of the wicket as he raced past his half-century.
Masood before the series promised his team would play a proactive brand and he led from the front by charging at offspinner Nathan Lyon and hitting him down the ground to good effect.
It was the type of domination rarely seen from Pakistan during more than two decades of misery in Australia, where they have lost 15 straight Test matches.
But Cummins took it upon himself to change the game with a magical five-over spell where he accounted firstly for Shafique with a brilliant return catch in his follow through.
Then he renewed his battle with Babar, who Pakistan desperately needed to stand up if they were to close in on Australia's first innings. Cummins in Perth had worked over Babar before having him nicked off in Pakistan's second innings.
He produced an even better delivery with a pearler that had late inward seam movement to befuddle Babar and hit the top of off stump. Having removed Babar for 1, Cummins leapt in the air in celebration and Pakistan could not recover from the dispiriting dismissal of their talisman.
Lyon exacted revenge when Masood, shortly after reaching his half-century, holed out attempting another big stroke. It was Lyon's second wicket having earlier removed opener Imam-ul-Haq in his first match since taking his 500th Test wicket in the series-opener.
In his 16th innings of a fledgling Test cricket, Saud Shakeel was dismissed for the first time under 20 when he was knocked over on 9 by a stellar delivery from quick Josh Hazlewood.
Cummins returned to the attack shortly before stumps and was met by an extraordinary six from recalled Mohammad Rizwan, who flicked him audaciously over deep backward square in a shot more reminiscent of white-ball cricket. But Cummins was not to be denied and capped what might prove to be a game-changing performance by dismissing allrounder Agha Salman.
Pakistan's hopes of avoiding a hefty first innings deficit rest with Rizwan, who was in aggressive form in his return having been contentiously overlooked for the first Test with selectors sticking with incumbent wicketkeeper Sarfaraz Ahmed.
Pakistan's calamitous finish negated their earlier hard work having clawed back into the game with seven wickets in a prolonged first session after Australia resumed on 187 for 3 following a rain-interrupted opening day.
Pakistan's quicks were backed up by a much better fielding effort. After several shoddy dropped catches so far this series, they hung on to tough chances in the outfield while wicketkeeper Rizwan produced a spectacular one-handed take diving to his right to dismiss counterpart Alex Carey.
But having enjoyed favourable bowling conditions, after Masood elected to field, Pakistan rued inconsistencies from their quicks while 52 extras bumped up Australia's total.
Spearhead Shaheen Shah Afridi's tough start to the series continued and he finished with 2 for 85 from 27 overs. He has been unable to consistently find the right length and his pace continues to be down in what has been a bane in recent times.
Quick Aamer Jamal continued his strong start to Test cricket with three wickets, including Marnus Labuschagne who top-scored for Australia with 63 in the only half-century in the innings. Having entered the match averaging just 35 in Test cricket this year, marked by troubles outside the off stump, Labuschagne looked far more assured as he navigated the tricky surface.
Labuschagne combined well with a confident Mitchell Marsh, who hit a quick 41 on the back of his twin half-centuries in Perth as he cements his position at No.6. But Australia lost their last six wickets for 68 as Pakistan's momentum continued into their batting until Cummins' unforgettable spell.
