Debutant spinner Maheesh Theekshana claimed four wickets as Sri Lanka hammered South Africa by 78 runs in the third one-day international to clinch the series 2-1 on Tuesday.
The hosts bowled out South Africa for 125 in 30 overs while chasing a target of 204 in Colombo. Theekshana, who picked up a wicket on his first ball in international cricket, returned figures of 4-37.
Earlier Sri Lanka posted 203-9 in their 50 overs after they elected to bat first with Charith Asalanka scoring 47.
The two sides will now play three Twenty20 internationals starting Friday at the same venue.
© Agence France-Presse