Sri Lanka's Hasaranga takes 7-19, Zimbabwe out for 96
Two downpours cut the game to 27 overs a side but the tourists still fell short as Hasaranga, who missed six months of cricket after a hamstring injury last July, cut through their batting with his googly.
Zimbabwe had a promising start with the openers putting on 43 for the first wicket.
Hasaranga joined the attack in the ninth over of the innings, after the first rain interruption, claiming opener Takudzwanashe Kaitano's wicket on his sixth ball to make a vital breakthrough.
Hasaranga sent back two more in his next over as Zimbabwe slumped to 47-3.
There was no recovery for the tourists as Hasaranga polished off the tail -- the fourth time he had taken five or more wickets in an innings.
Hasaranga's tally is a new record for R. Premadasa Stadium, eclipsing Angelo Mathews' 6-20 against India in 2009.
It was also the second best ODI figures by a Sri Lankan bowler behind 8-19 by Chaminda Vaas.
Sri Lanka lead the three-match series 1-0. The first game was washed out by rain while Sri Lanka won the second by two wickets.