Openers Phil Salt and Will Jacks blazed 77 at almost 10 runs per over after Jos Buttler won the toss at the Sir Vivian Richards Stadium and chose to bat.
Shai Hope’s bowlers then took advantage of a two-paced surface to pull the scoring rate down significantly before Sam Curran and Brydon Carse regained the frenetic early tempo in an eighth-wicket stand of 66 as 86 runs came off the final nine overs of the innings.
Brook’s 71 came off 72 balls with seven fours and two sixes as the West Indies bowlers mixed up the pace of their deliveries, spinner Gudakesh Motie and pacers Romario Shepherd and Oshane Thomas all claiming two wickets each.
In their first match since a disastrous World Cup defence in India, England opted to select only one specialist spinner in teenager Rehan Ahmed while the West Indies, who failed to qualify for the World Cup, chose two in Motie, the most economical of the bowlers, and Yannic Cariah.
West Indies are also giving an ODI debut to batsman Sherfane Rutherford.