England were made to wait to secure a place in Sunday's Under-19 Tri-series final as the United Arab Emirates secured their first win of the tournament by three wickets.
Victory in Dubai would have seen England progress to a final showdown with Pakistan, who they will now have to beat in their final group match on Friday to be assured of a place if the UAE defeat Pakistan on Wednesday.
England made 250 for nine, but a superb all-round display from Qazi Ayub denied them a third straight win against the UAE.
Having taken 4-22 from 10 overs with the ball, Ayub added 40 from just 34 deliveries with the bat, leaving Sharuk Ahmed to hit Harry Finch for the winning runs in the 50th over.
Ryan Higgins had led the way with the bat for England, making 75 from 87 balls including three sixes.
Rob Sayer and Miles Hammond also cleared the rope more than once as both made 32 to provide some late impetus.
Spinner Karl Carver then took 2-35 from 10 overs as the UAE were reduced to 140 for four, but Rohit Singh and Ayub put on 98 in 11 overs to turn the tide in favour of the home side.
Sussex all-rounder Finch and Yorkshire seamer Matthew Fisher then dismissed Singh for 70 and Ayub in successive balls. With Fisher also getting rid of Jay Joshi in the penultimate over, the hosts needed eight runs from the final set of six with three wickets remaining.
Ahmed hit Finch’s second ball for six to level the scores and took a single from the next to give the UAE a maiden victory in five tournament outings.