Pakistan fought back to inflict an eight-run defeat on England in the first of three Twenty20 matches.
Chasing 145, Kevin Pietersen (33) and Ravi Bopara (39) put England in a good position in Dubai but Umar Gul took 3-18 to revive Pakistan's hopes.
Needing 18 off Junaid Khan's final over, England's Graeme Swann and Jonny Bairstow finished short on 136-6.
Swann took 3-13 in Pakistan's innings but Shoaib Malik (39) and Misbah-ul-Haq (26) put on 71 in the hosts' 144-6.
Their stand proved crucial as England's batsmen fell just short in a tight run chase under the lights at the Dubai International Cricket Stadium.
England retained Pietersen at the top of the order where he had been so successful in the one-day series whitewash and brought back Bopara after a back injury, leaving out Alastair Cook.
Pietersen looked to dominate from the start and England, despite a maiden over from Gul, cruised to 40-0 after five overs.
But Pietersen, having flat-batted a powerful six to the previous ball, was out for 33 in the sixth over when Asad Shafiq took a well-judged catch right on the boundary edge off Shahid Afridi's bowling.
Craig Kieswetter was bowled trying to make room for a big hit and Eoin Morgan went for 14 to off-spinner Mohammad Hafeez's quicker ball.
Bairstow was almost out first ball, his reverse sweep just falling short of Saeed Ajmal at short third man, but Bopara looked determined to see England to a fifth consecutive win.
The Essex batsman smashed a straight six off Junaid and kept the scoreboard ticking along before walking across his crease and being bowled behind his legs by a Gul yorker.
Jos Buttler, having also stepped across his stumps in an attempt to flick Gul away, fell to a one-handed catch by Ajmal for three, and next ball Samit Patel was trapped leg before playing across the line of an inswinger as the pace bowler took two wickets in two balls.
Swann and the inexperienced Bairstow struggled to get the ball away, with spinner Ajmal conceding only four runs off the penultimate over to leave England needing 18 off the final over.
But left-arm seamer Junaid kept his discipline and ensured his side broke their losing run.
Earlier, Pakistan opener Awais Zia gave his side a bright start on his debut, hitting two powerful boundaries off Steven Finn's first over and then smashing the paceman for a six into the second tier of the stand in his next over.
ENGLAND'S TWENTY20 INTERNATIONALS IN 2012
lost by eight runs
18 Sept-7 Oct
ICC World Twenty20
Finn got his revenge with a well-disguised slower delivery which Zia lofted into captain Stuart Broad's hands for an easy catch at mid-off.
Swann dropped Hafeez off another slower delivery, this time from Jade Dernbach, but the spinner's second over halted Pakistan's momentum.
Swann got lucky with the dismissal of Shafiq when it looked like he had already broken the wicket with his elbow before claiming a run-out, as four wickets fell for eight runs.
Two balls later, Hafeez swept Swann straight to Bairstow and in the next over, Swann tempted Afridi down the pitch and the batsman flicked the ball straight to Morgan at mid-wicket.
Umar Akmal faced three balls before hoicking Swann horribly and Dernbach raced in to take a superb diving catch and hand the bowler a double-wicket maiden.
Malik and Misbah batted sensibly to get their side back into the match, both smashing a six each as Pakistan built their total.
They put on 71 before Malik was out to the last ball of the innings trying to hit Dernbach over the ropes but their partnership ultimately made the difference.
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