|Second Test, Abu Dhabi, day two:|
|Pakistan 257 v England 207-5|
A late Pakistan revival undid the good work of England's Alastair Cook and Jonathan Trott on day two of the second Test in Abu Dhabi.
The pair shared a second-wicket stand of 139 after captain Andrew Strauss managed only 11.
But after Trott (74) fell to Abdur Rehman, Saeed Ajmal accounted for Cook (94), Kevin Pietersen and Eoin Morgan to leave England 207-5, 50 behind.
Earlier, Pakistan lost their last three wickets for one run in 16 balls.
Following the speed with which they wrapped up the Pakistan tail, England looked to be heading for a position from where they could level the three-Test series when Cook and Trott were together at the crease.
But, when left-armer Rehman ripped one past a lazy prod from Trott and into the off stump, it sparked a collapse that saw the tourists lose four wickets for 41 runs.
Even after Trott's departure, England were firmly on top with Cook seemingly set for a 20th Test century.
However, when six short he was trapped leg before by an Ajmal doosra, and turned for the pavilion without asking for a review.
Worse was to follow when Pietersen advanced down the wicket and inside-edged to slip via his pad and, after a number of alarms, Morgan was caught at slip off Ajmal (3-67) from the last ball of the day.
The chaos of the final session was in stark contrast to the serenity of the first two of the day for England, for whom the failure of captain Strauss was the only blemish on near-perfect morning and afternoon stanzas.
After Stuart Broad (4-47) trapped Pakistan captain Misbah-ul-Haq lbw for 84 with the 10th ball of the day and James Anderson (2-46) accounted for Ajmal and Junaid Khan, Strauss offered a simple bat-pad chance to short leg off the bowling of Mohammad Hafeez.
Strauss and Cook had become the first England pair to open together in 100 Test innings - and fourth overall - but the departure of the skipper, who has now made only 292 runs in his last 13 innings, meant that they could not celebrate the landmark with a significant stand.
Instead it was left to vice-captain Cook and Warwickshire's Trott, with their sixth Test century partnership, to bat with patience and determination in order to put England in a position of strength.
They did, however, need some luck and the aid of Pakistan's poor use of the Decision Review System.
Left-hander Cook could twice have been caught at short leg off Hafeez, although replays did show one of the deliveries to be a no-ball that was not called.
Trott also had an escape, when Pakistan opted not to review an lbw appeal that was turned down, but which replays showed should have accounted for the right-hander.
Those alarms aside, Cook, strong through point and midwicket, and Trott, who scored off the front foot on both sides of the wicket, made steady progress until midway through the evening session.
Such was the ease with which runs were being accumulated, it came as a surprise when Rehman removed Trott.
It was the start of a frenzied hour that left the match, and England's hopes of levelling the series, hanging in the balance.