England were marginal favourites to level their three-match series against Pakistan thanks to Stuart Broad's runs and Monty Panesar's wickets by stumps on day three at the Zayed Stadium.
Broad's counter-attack brought him an unbeaten 58, and helped England to 327 all out and a precious lead of 70 in this second Test.
Then Panesar (three for 44) and Graeme Swann did the damage as Pakistan lost three wickets before they could reach parity, but recovered to 125 for four.
Broad and James Anderson's new-ball pace, as in the first innings, soon seemed unthreatening. But after Panesar entered the attack for just the sixth over, he began a run of three wickets for seven runs.
Mohammad Hafeez was lbw pushing forward to an arm ball from the left-arm spinner - and Swann struck in his first over with a straight-on delivery from round the wicket to Pakistan's other opener, the left-handed Taufeeq Umar, bowled between bat and pad.
A modicum of turn - not as much as Pakistan's spinners have found here - then saw Panesar snake one past Younus Khan's outside edge to hit the off-stump.
Pakistan lost their captain Misbah-ul-Haq, and a review, via the 21st lbw decision of this series in the first over of the last session.
But Asad Shafiq and Azhar Ali, billed together as the future powerhouse of Pakistan's middle order, demonstrated that potential in a determined stand of 71 which kept their team in this match.
The nearest England came to another breakthrough was Kevin Pietersen's rolled throw at the stumps which, if accurate, would have run Shafiq out for 26 after he had been sent back for an unlikely single to cover.
For his trouble, Pietersen appeared to trip over the batsman as his momentum took him into the crease and was soon off the field for medical attention. Broad and Ian Bell were the most successful this morning with an evident brief to grab as many runs as possible before Saeed Ajmal (four for 108) et al bowled them out in conditions tailor-made for their skills.
Employing tactics near polar opposite to Alastair Cook and Jonathan Trott's admirable crease occupation yesterday, Broad's invaluable ninth Test 50 contained six fours and a six over long-on off Abdur Rehman from just 52 balls.
He was unable to add to his lunchtime gains, though, because Hafeez (three for 54) hurried one through to bowl Anderson and then had number 11 Panesar lbw by similar method to leave Broad stranded. Ajmal managed to add only the dismissal of Matt Prior to the three quick wickets he took last night.
But if England's fightback was undermined then, Broad gave it new life in precarious circumstances today.
Pakistan should have been into the England tail almost immediately this morning, soon putting down two clear-cut chances.
Prior did not make them pay, but Bell did a little.
Junaid Khan allowed an aerial sweep at Ajmal to slip through his fingers at deep backward-square, but Prior added only that run before the same bowler had him lbw on the back foot - even after a DRS review.
Bell would have gone for just nine had Rehman clung on to a fiercely-struck return chance which instead went for the first of two successive fours.
England's last front-line batsman continued to look for scoring opportunities, but not so avidly as his new partner Broad.
The seventh-wicket pair scored a psychological blow when Misbah-ul-Haq abandoned Plan A to bowl them out with spin - calling for the second new ball after 98 overs.
Broad stayed on the attack, and the second of two boundaries from Umar Gul's first over with the new ball - a thick edge wide of the slips - took England in front.
Bell lasted little longer, lbw on the back-foot defence to Gul and using up the final review for good measure but to no effect. But Swann lent Broad a hand too until he also went lbw, this time pushing forward to Rehman.
Anderson was another handy ally for Broad up to lunch, to account for a mid-match runs advantage which left the game in the balance, allowing for the likely difficulty of chasing a target in the fourth innings on an already awkward surface.
The eventual outcome was no easier to call two sessions later.