Left-arm spinner Imad Wasim chipped in with 3-21 — nine wickets in the series — as West Indies crawled to 103-5 in their 20 overs after Pakistan won the toss and decided to bowl first.
Marlon Samuels, who top-scored with a 59-ball 42 not out, added 37 for the unbroken sixth-wicket stand with Kieron Pollard, who made an unbeaten 16.
Pakistan wipes off the target in 15.1 overs, with Shoaib Malik (43 not out) and Babar Azam scoring an unbeaten 27.
Pakistan won the first two matches by nine wickets and 16 runs respectively — both in Dubai.
The two teams will now play a three-match one-day series starting in Sharjah on Friday.
Pakistan captain Sarfraz Ahmed won the toss and sent West Indies into bat in the third and final Twenty20 international in Abu Dhabi on Tuesday.
They brought in fast bowlers Mohammad Amir and Rumman Raees for Wahab Riaz and Hasan Ali from the line-up of the Saturday’s second game. West Indies also made two changes, bringing in Chadwick Walton and Kesrick Williams for Samuel Badree and Evin Lewis.
The 24-year-old Raees played his first international match while Williams debuted for the West Indies.
J. Charles b Wasim 5
A. Fletcher run out 9
C. Walton b Wasim 0
M. Samuels not out 42
D. Bravo b Wasim 11
N. Pooran c Malik b Nawaz 16
K. Pollard not out 16
Extras: (lb 3, w 1) 4
Total: (for five wkts; 20 overs) 103
Did not bat: C. Brathwaite, S. Narine, J. Taylor, K. Williams
Fall of wickets: 1-12 (Charles), 2-12 (Walton), 3-17 (Fletcher), 4-31 (Bravo), 5-66 (Pooran)
Bowling: Wasim 4-1-21-3, Tanvir 4-0-22-0, Nawaz 3-0-16-1 (1w), Amir 4-0-20-0, Malik 2-0-11-0, Raees 3-0-10-0
Sharjeel Khan c Fletcher b Williams 11
Khalid Latif b Williams 21
Babar Azam not out 27
Shoaib Malik not out 43
Extras: (lb 4, w 2) 6
Total: (two wkts; 15.1 overs) 108
Did not bat: Sarfraz Ahmed, Umar Akmal, Imad Wasim, Mohammad Nawaz, Sohail Tanvir, Mohammad Amir, Rumman Raees
Fall of wickets: 1-36 (Sharjeel), 2-40 (Latif)
Bowling: Taylor 2-0-19-0 (1w), Williams 4-0-15-2 (1w), Bravo 4-0-31-0, Narine 4-0-21-0, Brathwaite 1.1-0-18-0
Result: Pakistan win by eight wickets
Umpires: Ahsan Raza (PAK) and Shozab Raza (PAK)
Tv umpire: Ahmed Shahab (PAK)
Match referee: Andy Pycroftt (ZIM)
Man of the Match: Imad Wasim
Man of the Series: Imad Wasim