Man-of-the-match Sarwan struck five fours and a six in 58 balls as West Indies totalled 159 for four in reply to Bermuda's 158-9 at the Maple Leaf Cricket Club.
Left-hander Shawn Findlay weighed in with a whirlwind 41 to help the tournament favourites cruise to victory with 18.1 of their 50 overs to spare.
Bermuda, playing West Indies for the first time in a one-day international, struggled after being asked to bat first. Chris Douglas, one of only four batsmen to reach double figures, top-scored with 53.
In the absence of injured fast bowler Fidel Edwards, Kemar Roach was the spearhead of the West Indian attack, taking two for 29 in 10 overs of fast-medium seam. Slow-left armer Nikita Miller took 3-19.
West Indies face hosts Canada on Friday before the two sides meet again in the tournament final on Sunday.
