|Pakistan must win to level the two match series after losing at Lord's. Australia are seeking an eighth consecutive test victory [Reuters]
Pakistan's Mohammad Aamer claimed wickets with the first two balls after lunch to help reduce Australia to 88 all out for their lowest test total in 29 years on the first day of the second test on Wednesday.
Left-arm fast bowler Aamer, aged 18, first bowled Steven Smith with a ball that swung into him sharply to make it 73 for seven in bowler-friendly conditions at Headingley.
Then left-hander Mitchell Johnson looked to drive a delivery heading for his leg stump through mid-on only to see the ball swing prodigiously away from him to smash into his wicket.
The hat-trick ball to Ben Hilfenhaus was also good, passing the outside edge of the bat close enough to excite the smattering of Pakistani fans in the sparsely filled stadium.
The final wickets fell when Hilfenhaus, attempting a second run, was run out by Umar Amin, and Tim Paine edged Mohammad Asif behind for a top score of just 17.
Australia were bowled out in 33.1 overs at 1400 (1300GMT).
Australia's most recent lowest total was 83 against India in 1981.
Aamer finished with figures of three for 20, Asif claimed three for 30 and Umar Gul took two for 16.
Australia captain Ricky Ponting earlier won the toss and batted despite overcast conditions that favoured the bowlers helped by heavy overnight rain.
England were bowled out for 102 at the ground on day one against Australia last year after deciding to bat first.
Pakistan must win to level the two-match series after losing at Lord's.
Australia are seeking an eighth consecutive test victory.