Karachi (AFP) - Australia grabbed the key wicket of Imam-ul-Haq after setting Pakistan a record 506 runs to win the second Test in Karachi on Tuesday.
Pakistan were 18-1 at lunch on the fourth day, with Abdullah Shafique unbeaten on 14 and Azhar Ali three on a low-bouncing and turning National Stadium pitch.
The hosts need another 488 runs to win -- the highest successful fourth innings run chase in Test history is 418 -- or more likely need to survive five sessions for a draw.
Australia, resuming their second innings at 81-1, batted for just 26 minutes at the start of play to add 16 runs before declaring on 97-2 when the wicket of Marnus Labsuchagne fell.
The visitors scored 556-9 declared in their first innings then dismissed Pakistan for 148.
Haq and Shafique were all caution as it took them until the fifth over to score the first run, before off-spinner Nathan Lyon struck.
The in-form Haq, who scored a hundred in each innings of the drawn first Test in Rawalpindi, was trapped lbw for one as he failed to connect with a sliding delivery.
Earlier, Labuschagne was bowled off a sharp Shaheen Shah Afridi delivery for 44 to prompt captain Pat Cummins to call the innings to a close with first-innings century-maker Usman Khawaja, who was born in Pakistan, remaining 44 not out.
Australia are on their first tour of Pakistan since 1998, having previously refused to tour the country because of security fears.
