Sarwan played sheet-anchor after his side were reduced to 65 for four in the 20th over to take West Indies score to 253 for eight in 50 overs after they were put into bat at the R Premadasa Stadium.
Coming in to bat in the 10th over with his side reeling at a precarious 32 for three, Sarwan single-handedly took West Indies to a competitive total. He took the Kenyan bowlers to task and hit 11 fours and five sixes in his 125-ball innings.
Chasing a stiff target of 254, Kenya were shot out for 192 in 45.3 overs with paceman Andre Russell claiming four for 43 in his 10 overs as West Indies won the match easily to boost their morale ahead of the World Cup.
West Indies made a wobbling start with their opening batsmen Devon Smith (0) and Adrian Barath (17) were dismissed cheaply with just 32 on board, both falling to veteran pacer Thomas Odoyo.
One-down Darren Bravo did not stay long at the crease as he also fell for just 12 to leave Sarwan with a huge task of doing a rescue act.
Former captain Shivnarine Chanderpaul contributed just seven and it was left to Sarwan and all-rounder Dwayne Bravo to take the side out of the woods.
The duo did that in superb fashion with a 94-run stand for the fifth wicket from 15.3 overs, taking their side from 65 for four to 159 for five in the 35th over when Bravo was out for a 56-ball 54 which was studded with six fours and a six.
The duo also pushed up the scoring rate with some lusty blows, giving off-spinner James Ngoche (0/41 from five overs) some special treatment.
Sarwan shepherded the tail admirably well and took most of the strike while also scoring at a brisk pace.
West Indies added nearly 100 runs from the remaining 15 overs after Bravo was out and the bulk of them came from Sarwan`s blade.
Captain Darren Sammy, Carlton Baugh and Andre Russell could contribute just seven, 12 and four not out respectively.
Odoyo was the most successful Kenyan bowler with three for 34 while Steve Tikolo chipped in with two for 32.
Kenya began their run chase on a strong note though they lost their opening batsman Alex Obanda (15) early.
The other opener Seren Waters (43) and one-down Collins Obuya (68) raised 70 runs for the second wicket to keep their side in the hunt for a successful run-chase.
The asking rate, however, caught up with the Kenyans and their middle-order collapsed in a heap while trying to accelerate the run chase.
Once Obuya was out in the 39th over at 152 for four, the remaining six Kenyan batsmen fell in quick succession to fold up the innings at 192, after adding just 40 runs in 7.2 overs.
Russell polished off the tail with three late dismissals, apart from the wicket of opener Obanda earlier. Russell`s fellow pacer Kemar Roach took three for 23.
West Indies play their second and final warm-up match against Sri Lanka at the same venue on Tuesday while Kenya take on the Netherlands at the Sinhalese Sports Club Ground here on the same day.
Brief Scores: West Indies 253/8 in 50 ovs (R Sarwan 123, Dwayne Bravo 54, T Odoyo 3/34, S Tikolo 2/32). Kenya 192 in 45.3 ovs (Seren Waters 43, C Obuya 68). WI won by 61 runs.