Bridetown: Mohammad Hafeez's second career hundred was upstaged by rain and a blistering 76 from Lendl Simmons that condemned Pakistan to a one-run defeat under the Duckworth-Lewis Method in the fourth one-day international on Monday.
Pakistan were left to nurse their wounds, when the inclement weather that has dogged this island over the last week interrupted, as West Indies were chasing a revised target of 223 from 39 overs.
For the West Indies it ended a run of eight straight defeats in this format of the game by Pakistan and a recent run of six successive defeats against all opposition.
A short ball from Pakistan captain Shahid Afridi was swung high over mid-wicket for six by Dwayne Bravo to formally carry West Indies to 154 for four - the exact total they required - from 29.5 overs under the D/L Method to claim their first victory of the series.
Pakistan lead the five-match series 3-1 with the final ODI to be played on Thursday at the Guyana National Stadium.
Pakistan had stumbled, after Hafeez struck seven fours and three sixes in the top score of 121 from 138 deliveries, and shared a century second-wicket stand with Asad Shafiq to lead the visitors to 248 for nine from their allocation of 50 overs.
After the Pakistanis were sent into bat on a hard, true Kensington Oval pitch under overcast skies, Hafeez anchored the batting, and reached his milestone from 128 balls with a flick through mid-wicket for a single off Ravi Rampaul in the 42nd over.
He added 153 for the second wicket with Shafiq, whose 71 from 102 balls contained four boundaries, before leg-spinner Devendra Bishoo continued to bowl impressively, taking three for 37 from his allotment of 10 overs to trigger a batting collapse.
The visitors lost their way in the last 10 overs, losing seven wickets for 66 runs, to slide from a comfortable 182 for two, with Dwayne Bravo taking two for 60 from his 10 overs, Kemar Roach two for 67 from 10 overs, and two run outs helping to undermine them.
Junaid Khan set West Indies back early, when he had makeshift opener Kirk Edwards caught behind for a first-ball duck in the second over.
But Pakistan were put on their heels, when Darren Bravo joined compatriot Simmons, and they put on 56 for the second wicket with a volley of strokes.
Tanvir Ahmed was the target for some special treatment from Bravo and Simmons, when they smote three fours and one six from his fourth over.
Khan made the breakthrough, when Bravo was caught at third man for 21, but Ramnaresh Sarwan, making a return to the side for the first time since losing his place following the World Cup, kept the momentum going with 28 in a stand of 75 with Simmons.
Hafeez showed his all-round ability, when he had Sarwan caught at long-off for 28 in the 25th over before Tanvir gained his revenge on Simmons, when the West Indies opener was caught on the cover boundary in the next over to leave the home team 135 for four.
Pakistan's bowlers tried to tie down the West Indies pair of the elder Bravo and Marlon Samuels, but they failed, and West Indies could celebrate a victory at long last.
Brief scores
Pakistan 248 for 9 (Hafeez 121, Shafiq 71)
West Indies 154 for 4 (Simmons 76)
Results West Indies won by one run - D/L
MOM Mohammad Hafeez (Pakistan)