Sri Lanka, set a modest 218 to win, wobbled in the middle before reaching their target in 47.5 overs with Tillakaratne Dilshan (73) and skipper Kumar Sangakkara (54) setting the foundation at a packed R Premadasa stadium.
Muralitharan took his 534th wicket off his last ball on home soil as New Zealand were bowled out for a below-par score of 217 in 48.5 overs.