West Indies all-rounder Dwayne Smith dominated with bat and ball to ensure the World Cup hosts opened the competition with a 54-run victory over Group D rivals Pakistan at Sabina Park on Tuesday.
West Indies scored 241 for nine and then bowled Pakistan out for 187.
It marked a superb return to form after they were crushed by India by nine wickets, having been skittled for 85 in their final warm-up game on Friday.
Batting at number eight, man-of-the-match Smith's cameo of 32 from 15 balls pushed his side to a competitive total and then his medium-pace bowling turned the game in West Indies' direction.
He claimed the vital wickets of Mohammad Yousuf and Pakistan skipper Inzamam-ul-Haq in a return of three for 36.
It was an impressive performance from the Caribbean side, with major batting contributions from Marlon Samuels (63), Ramnaresh Sarwan (49) and captain Brian Lara making 37. Later seamer Dwayne Bravo took three for 42.
The victory gives the West Indies pole position in the group, ahead of their games against Zimbawbe and Ireland, and two points to take into the Super Eights stage, presuming both they and Pakistan qualify.