One-day tour match, Trinidad:
England 299-8 (50 overs) beat West Indies Players Association XI 248
Mascarenhas carves the ball through the off-side field at Guaracara Park
England were guilty of some lax bowling before gaining a 51-run win over the West Indies Players' Association XI.
Gareth Batty and Adil Rashid conceded 86 runs in 15 overs as Samuel Badree and Kenroy Williams forged a 114-run stand after they had been 100-7.
But Jimmy Anderson dismissed Williams for 60 as part of a three-wicket haul while Steve Harmison claimed 4-55.
Earlier Dimitri Mascarenhas hit 84 to lead England to a total of 299-8 in the one-day warm-up in Trinidad.
The tourists had rested several key players including captain Andrew Strauss, Paul Collingwood and Kevin Pietersen ahead of Sunday's Twenty20 international.
But Ravi Bopara (56) and acting skipper Ian Bell (55) laid a solid foundation.
And Mascarenhas shared a stand of 67 with Rashid before upping the scoring rate in the closing overs.
It was exactly the sort of performance the powerful Hampshire all-rounder was hoping for in his first game for England since last summer.
But not everything went according to plan for England, who are hoping to bounce back strongly from a 1-0 Test series defeat in the second half of the tour.
Worcestershire's Steven Davies opened the batting at Guaracara Park after joining the party from the England Lions tour in New Zealand, but he only managed two before his off stump was knocked out by Atiba Allert.
Bopara had a let off on 19 when he was dropped at mid-wicket and went on to hit five fours and a six before being stumped after advancing down the pitch.
Bell added a half-century of his own in a welcome return to form after being dropped from the Test side, but his exit sparked a mid-innings slump which also saw the downfall of Owais Shah and Matt Prior.
Mascarenhas and Rashid maintained their concentration well through two rain interruptions to halt the slide.
And Mascarenhas made the home side pay for dropping him on 71 as the final three overs of the innings yielded 33 runs.