Off-spinner Saeed Ajmal took three wickets in five balls to leave England struggling at 52-5 at lunch on the opening day of the first Test played at Dubai Stadium on Tuesday.
The 34-year-old, whose claims of a mystery delivery surrounded the lead-up to the three-Test series, came into his own after being introduced in the 19th over, leaving England, who decided to bat on a slow turning pitch, in an early spin.
Ajmal dismissed Andrew Strauss (19) with the last delivery of his first over and then had Ian Bell (nought) with the first ball of his next before trapping Kevin Pietersen (two) leg before three balls later.
Ajmal, who has figures of 5-3 could have had his fourth wicket had Adnan Akmal stumped Morgan who was beaten all ends up while coming out to drive but the wicket-keeper failed to gather the ball cleanly.
The early success of Pakistan, who chose Ajmal and left-armer Abdul Rehman as two spinners, would leave England rueing their decision to leave out the in-form Monty Panesar and play three seamers alongside off-spinner Graeme Swann.
Pakistan introduced spin as early as in the sixth over but it was Mohammad Hafeez and not Ajmal who came onto bowl and was instantly rewarded when England opener Alastair Cook edged his third delivery to Adnan after scoring three.
Paceman Aizaz Cheema then had Jonathan Trott (17), caught behind by a diving Adnan off a leg-side edge to leave England at 31-2.
Ajmal, who threatened to unveil a mystery delivery against England during the series, then bowled Strauss who went for a pull but missed the ball as well as his off-stump.
Bell was then caught and bowled off a straight delivery from Ajmal.
Pietersen survived a confident appeal but Ajmal asked for the Decision Review System which forced umpire Billy Bowden to change his decision, much to the amazement of Pakistan team.