Despite losing the series 3-2, Pakistan finished much stronger of the two sides in a rain-interrupted contest.
The visitors were sent in to bat first after losing the toss, and openers Muneeba Ali (39) and Sidra Ameen (13) went straight to work, building a 40-run stand to kick-start their innings.
Shabika Gajnabi (2/26) was the first to strike for West Indies with the dismissal of Ameen in the 11th over before Hayley Matthews got in on the action one over later, taking down Javeria Khan (1).
The following partnership, worth 49 runs, between Ali and Omaima Sohail (34) proved to be pivotal for Pakistan as they trucked along to 157/6 at the 30th over mark.
With four overs remaining in a shortened innings due to a delayed start, Fatima Sana struck an unbeaten 28 off 19 balls, including four boundaries, to bring Pakistan's total up to 190/8.
Set a revised target of 194, West Indies captain Deandra Dottin took to the task well, recording 37 off 47 before being bowled by Sana (5/38) in the 15th over.
It was the first of many for Sana, who pushed on to clinch her first career five-for with figures of 5/38 off seven overs.
Britney Cooper top-scored for West Indies with 39 as the hosts lost wickets at regular intervals to be bowled out for 169 on the final ball of the match.
Fatima Sana is player of the match as Pakistan beat West Indies by 22 runs.— ICC (@ICC) July 18, 2021
Successive wins for Pakistan but West Indies win the series 3️⃣-2️⃣!#WIvPAK | https://t.co/NLhN3ItIfq pic.twitter.com/tZ2VYvyq6a
With a brilliant 28* topped off with a five-wicket haul, 19-year-old Fatima Sana was named Player of the Match.
The Player of the Series was West Indies all-rounder Hayley Matthews, who finished the five-game affair with seven wickets and 168 runs, including 100* in the third ODI.