The match had become ill-tempered in the 21st over.
Sri Lanka slumped after opening batsman Danushka Gunathilaka was given out for obstructing the field and lost by eight wickets to the West Indies on Wednesday in the first one-day international.
Gunathilaka made 55 and put on 105 in an opening stand with captain Dimuth Karunaratne, which seemed to put Sri Lanka on course to a commanding total after it lost the toss and had been sent in.
Karunaratne was out for 52, caught and bowled by West Indies captain Kieron Pollard with his second delivery.
The match became ill-tempered when, in the 21st over, Gunathilaka was judged to have obstructed the field when he trod on the ball while Pollard was attempting to affect a run out.
Pollard bowled a short ball which Gunathilaka fended away. Pathum Nissanka set off for a single but Gunathilaka, after advancing down the pitch, sent him back and stepped back into his own crease. As he did so, he stepped on the ball and knocked it backwards.
Pollard immediately appealed and on-field umpire Joe Wilson gave a soft signal of out before television umpire Nigel Guguid ruled that Gunathilaka had deliberately attempted to foil the run out. There seemed to be little evidence the batsman had acted deliberately.
The Sri Lanka innings lost its way from then on and the tourists were all out for 232 in 49 overs. The West Indies surpassed that total with Shai Hope making 110 and his opening partner Evin Lewis adding 65.
“We got a nice start but but we lost a couple of wickets,” Karunaratne said. “In the end we were short of 30-40 runs. If me and Danushka could have batted longer it would have been a different story.”
Karunaratne said 232 was inadequate on a good batting pitch.
“They could just get singles and rotate the strike,” he said. “Shai got a start and he batted well. We kept losing wickets in our innings.”
Pollard acknowledged the dismissal of the Sri Lanka openers in quick succession with the total 105, and 112, changed the course of the innings and the match. Angelo Mathews (5) followed at 119 and Nissanka (8) when Sri Lanka was 126-4.
A half century by Ashen Bandara lifted the Sri Lanka total but he lacked support. Dinesh Chandimal (12) and Lakshan Sandakan who was left 16 not out were the only other Sri Lanka batsmen to reach double figures.
“They were 100 without loss and we were looking at a chase of 300,” Pollard said. “We thought we needed to up the intensity in the field. “They lost a couple of wickets and it started the slide.”
Pollard praised Hope’s match-winning innings.
“For us in white-ball cricket, Hope is the guy,” he said. “He’s been given a role and he gives us the foundation and others can bat around him.”