Spinner Maheesh Theeksana claimed four wickets for 37 runs on debut and helped Sri Lanka beat South Africa by 78 runs in a low-scoring third and final One-dayer at the Premadasa Stadium here on Tuesday.

Chasing a target of 204, South Africa's innings failed to take off as they were bundled out for 125 in 30 overs. Sri Lanka won the series 2-1 after South Africa had won the second ODI to level the series 1-1.