Samiullah Shenwari top-scored for Afghanistan with 58 as their whole batting line-up chipped in with double-figure scored in a total of 308-9 in their 50 overs.
Khurram Khan impressed with a 70-ball 86 in reply but it proved to be in vain as the UAE fell short or their target, bowled out for 294 in the 49th over.
Afghanistan won the toss and chose to bat but struggled early on, losing three wickets in their first 10 overs ??? UAE???s Amjad Javed (4-39) accounting for two of them.
Shenwari helped steady the ship and received good support from Asghar Stanikzai (33), Mohammad Nabi (30) and Najibullah Zadran (46) in the middle-order.
But all were guilty of not converting their good starts into bigger scores and when Shenwari fell in in the 44th over ??? another of Javed???s victims ??? Afghanistan were only 226-7.
But some blistering lower-order hitting from numbers 10 and 11 ??? Mirwais Ashraf (34 off 17 deliveries) and Gulbadin Naib (24 off 10) ??? helped them score 82 runs off the final six overs and post a stern target of 309 to win.
It didn???t faze the UAE as they raced out of the blocks in their innings, going at almost 10 runs per over in their first six overs till their first wicket fell at 61-1 in the seventh over ??? Amjad Ali (26 off 24).
AR Berenger (39) and Krishna Chandran (49) were guilty of not converting starts much like the Afghanistan batsmen, but Khan did kick on, reaching a well-deserved fifty.
His wicket in the 41st over would proved to be key ??? he fell lbw to Aftab Alam (3-43) ??? with UAE needing only 65 from 57 balls with six wickets in hand at the time.
But it signalled a collapse with three wickets falling for nine runs, before Rohan Mustafa (24) and Javed (18) had them creeping again towards the target.
Both fell in the 48th over though and the match was wrapped up the next over.
Afghanistan play Bangladesh on Wednesday in their first World Cup match while the UAE kick-start their campaign against Zimbabwe the following day.