Australia 145 (Abbas 5-33, Bilal 3-23) and 47 for 1 need another 491 runs to beat Pakistan 282 (Fakhar 94, Sarfraz 94, Lyon 4-78, Labuschagne 3-45) and 400 for 9 dec (Babar 99, Sarfraz 81, Lyon 4-135)
Abu Dhabi: Babar Azam fell one run short of his maiden century as Pakistan set Australia a mammoth victory target of 538 on day three of the second and final test in Abu Dhabi on Thursday.
Australia then lost opener Shaun Marsh as the visitors ended the day on 47-1 and facing an uphill battle to avoid defeat after Pakistan declared their second innings on 400-9.
Paceman Mir Hamza sent back Marsh for four before Aaron Finch (24) and Travis Head (17) steadied the ship, although Australia's hopes of a first series win in Asia since 2011 were hanging by the slenderest of threads with 491 runs still needed.
Azam hit six fours and three sixes in his 171-ball knock before falling leg-before to Mitchell Marsh as he closed in on a deserved century. He put on a 133-run stand with skipper Sarfraz Ahmed (81) for the sixth wicket.
Ahmed also failed to convert his aggressive knock into a century, as he was dismissed leg-before while looking to sweep spinner Marnus Labuschagne.
Earlier, Asad Shafiq and Azam provided stability in the middle order after Pakistan lost a couple of early wickets as the hosts stretched their lead to 369 at lunch.
Resuming the day on 144-2, Pakistan lost the wicket of Haris Sohail (17) when he was stumped by visiting captain Tim Paine off a tossed up delivery from off-spinner Nathan Lyon.
Sohail's overnight partner Azhar Ali (64) was then run out in a bizarre fashion when he edged a Peter Siddle delivery fine of gully and walked up the pitch for a chat with partner Shafiq, thinking the ball was running safely to the boundary.
Mitchell Starc, who is nursing a tight hamstring, picked up the ball that had ground to a halt just inside the rope before sending a throw for wicketkeeper Paine to whip off the bails with both batsman standing idly in the middle of the strip.
Australia were dismissed for 145 on day two, handing Pakistan a 137-run first innings advantage.