(CNN) -- Captain Mohammad Yousuf will hold the key as Pakistan chase a record 422 for victory after Shane Watson's maiden Test century gave Australia the upper hand heading into the final day of the first Test at the Melbourne Cricket Ground.
Yousuf (45 not out) and exciting youngster Umar Akmal (27 not out) steered the visitors to 170 for three at stumps on day four, still requiring a further 252 runs with seven wickets remaining to pull off what would be the most successful run chase in Test history.
Ricky Ponting earlier declared Australia's innings closed on 225 for eight midway through the second session with Watson remaining unbeaten on 120.
To win, Pakistan must surpass the highest-ever successful run chase of 418 made by West Indies in their defeat of Australia at St John's in 2003.
Having come so close on three previous occasions already this summer, Watson finally broke through for his first Test ton shortly after lunch -- but only after being dropped on 99.
The Queenslander spent 67 agonising minutes and 39 balls in the 90s before eventually reaching triple figures for the first time.
In front of just over 15,000 fans, Watson, who had fallen short of a first Test century with scores of 96, 89 and 93 this summer, converted his seventh Test fifty into a ton after yet another dropped catch from the tourists.
Pakistan have been plagued by poor fielding in recent times and have grassed five opportunities in this match alone.
It follows a poor tour of New Zealand in which Pakistan dropped six catches in one innings in Wellington.
This match, however, now rests in the hands of their batsmen after Australia forged into a formidable lead on the penultimate day, despite the efforts of Mohammad Aamer, who finished with figures of five for 79.
The 17-year-old had threatened to turn the match in Pakistan's favor with his first five-wicket haul in Test cricket, tearing through the Australia middle-order in the first session to reduce the hosts to 161 for six.
Aamer captured three wickets in the space of 16 balls to have Australia on the ropes.
Playing in his seventh Test, he took the wicket of Michael Clarke for 37 before following up with Marcus North (six) and Brad Haddin for a duck two balls later as Pakistan took the fight up to the hosts.
Clarke and Watson put on 103 runs for the fourth wicket before the vice-captain was caught behind by Kamran Akmal.
North was dropped on one by Farhat at mid-wicket but failed to make the visitors pay as just five balls later he was on his way back to the pavilion for eight after mistiming a pull shot and dragging the ball back onto his stumps.
Haddin was out two deliveries later for his first duck in Test cricket after nicking a ball through to wicketkeeper Akmal.
Watson brought up his milestone when he drove at a full delivery from Aamer in the third over after lunch that flew straight through the hands of Abdur Rauf at backward point.
The 28-year-old managed a wry smile as he strolled through for a single before raising his arms in celebration as he became the first Australian to make a Test century since Michael Hussey against England at The Oval in August.
Mitchell Johnson brought up a milestone of his own when he became just the fifth player in history to score 500 runs and take 50 wickets in a calendar year.
He follows Ian Botham, Kapil Dev and Richard Hadlee, who all managed the feat twice, and New Zealand captain Daniel Vettori who achieved it last year.
The Australia paceman was run out shortly after the lunch interval for 22.
Nathan Hauritz was the last man out for eight, stumped by Akmal off the bowling of spinner Saeed Ajmal, before Ponting declared.
Doug Bollinger (one for 31) claimed the first breakthrough of the second innings when he had Imran Farhat trapped in front for 12.
The lbw shout was initially turned down by umpire Rudi Koertzen before the hosts referred the decision to the third umpire, who ruled in favor of the bowler.
But Iqbal Faisal and Salman Butt steadied the ship for Pakistan with the former particularly brutal with any short deliveries, smashing a four off Johnson and a six off Hauritz in consecutive overs.
Johnson (one for 36) had the last laugh shortly after when he caught Butt plumb in front for 33.
And when Iqbal, on the verge of a half-century, was deceived by a fiercely spinning Hauritz delivery and bowled for 48, Pakistan were staring down the barrel at 116 for three.
They were lucky not to lose another wicket shortly before stumps when Hauritz dropped a difficult chance from Akmal from the bowling of part-timer Simon Katich.