Pakistan 148 and 114 for 1 (Butt 58*, Azhar 28*) need 326 more runs to beat Australia 253 and 334 (Katich 83, Hilfenhaus 56*, Gul 4-61)
Scorecard and ball-by-ball details
Teams facing the prospect of a world-record run-chase generally find themselves praying for rain at some stage of the proceedings, but Pakistan have never been the most conventional of outfits. When play resumes for Friday's fourth day, every batsman in the "home" dressing room will be praying for skies as cloudless as those that they might expect in Karachi at this time of year, as they set their sights on a marathon target of 440 to win the first Test against Australia.
It is an outlandish notion, especially given that the same 11 cricketers crumbled to 148 all out in Pakistan's first innings, but such is the effect that the weather has on Lord's. When the atmosphere is heavy, the ball does handstands, but when the sun breaks through, the pitch becomes as flat as Faisalabad - as Salman Butt and the debutant Azhar Ali demonstrated in taking Pakistan's score to a confident 114 for 1 in 37 overs at the close of the third day.
The only breakthrough came when Imran Farhat suffered a rush of blood against Steven Smith, and wiped a horrid cross-batted mow to Shane Watson at midwicket to give the young legspinner his maiden Test wicket. Butt on the other hand chose his shots far more responsibly, to push confidently along to an unbeaten 58 - his second half-century of the match. Alongside him, the 25-year-old Azhar displayed a calm assurance in a tense scenario, even though Ben Hilfenhaus might well have capped a personally memorable day by pinning him lbw for 28 from the very last ball of the day.
And so the match boiled down to a simple equation. Pakistan need a further 326 runs for victory, Australia need nine more wickets in six sessions. It was a scenario reminiscent, in fact, of Australia's last visit to Lord's in 2009, when England assumed the match was in the bag as the Aussies chased a massive 522 in the fourth innings, only for Michael Clarke and Brad Haddin to run them uncomfortably close as they finished on 406. It took a never-say-die intervention from Andrew Flintoff to overcome the conditions (and the opponents) that day. Australia won't want history to have to repeat itself.
This time around, the third morning dawned as both of the first two had done, with dank skies overhead and all sorts of opportunities for Pakistan's seamers to capitalise on their late burst of four wickets in 10.1 overs on the previous evening. The fact that they were thwarted was almost entirely thanks to the determination of Australia's opener, Simon Katich, who batted 174 balls for an invaluable 83 - a performance that, in addition to his first-innings 80, looked sure to have him nailed down for the Man of the Match award.
But then, midway through the afternoon session, with Australia's innings ebbing away on 208 for 8, the heavens cleared and the context of the contest was transformed. Each of Australia's three remaining batsmen - the debutant wicketkeeper Tim Paine, and Nos. 10 and 11, Hilfenhaus and Doug Bollinger - recorded their Test-best scores as Pakistan's seamers found that the ball was now refusing to budge an inch from the straight and narrow.
Hilfenhaus's previous best had been an insubstantial 20, but he bettered that in boundaries alone, as he took the long handle to a conveyor belt of dispirited bowlers, not least Mohammad Asif, who had been so deadly under the cloud cover, but now suffered the indignity of being cracked over the covers for a nose-rubbing six.
For Paine, the contrast between first innings and second could scarcely have been more stark. On Tuesday he had laboured to 7 from 46 balls as Asif and Mohammad Aamer kept him under the cosh. Now he found himself cruising to 47 from 85, in a ninth-wicket stand of 74. His one moment of discomfort came on 4, when Umar Gul bent his back to nip a lifter into his nether regions, but it was quite some surprise when he played around a full-length delivery from Afridi to be bowled on the brink of his maiden half-century.
After picking up the solitary wicket of the nightwatchman, Mitchell Johnson, in the morning session, Pakistan had resumed after lunch with one of their typically intermittent bursts of inspiration, when Gul and Asif struck within three balls of one another to remove both not-out batsmen, Katich and Marcus North (20) without addition to the score. When Smith fell lbw to the second ball of Danish Kaneria's new spell, three key wickets had fallen for 20, and Australia's advantage - 313, with two wickets standing - didn't look quite so insuperable.
But then the sun peeked through the clouds for the first time in eight sessions, and Australia's tail wagged to such violent effect that the end-of-innings scorecard looked like an administrative error, with nine men reaching double figures, but none other than Ricky Ponting and Michael Hussey making ducks. It was a fact that highlighted how much the game had changed. A contest that had started with a clatter of wickets looked set to be decided amid a deluge of runs. Australia remain overwhelming favourites, but if the clouds stay away, Pakistan could yet make them toil.
Andrew Miller is UK editor of Cricinfo