South Africa A suffered a 160-run defeat to Sri Lanka A in the first four-day match in Pallekele.
Having been set a daunting target of 346 to win on day three, the visitors were bowled out for 185.
Keegan Petersen and Senuran Muthusamy both scored 29, with Sinethemba Qeshile (23), Dewald Brevis (20) and Lizaad Williams (19*) making the other notable contributions.
Earlier, Muthusamy took 5-53 – to go with his first-innings figures of 7-123 – as the hosts were bowled out for 151 in their second innings. Ramesh Mendis top-scored with 46.
The second four-day match will start in Dambulla next Monday.