Star all-rounder Jacques Kallis was ruled fit to play after overcoming a neck injury that he picked during one of the practice sessions.
The second one-dayer will be played in Pallekele on Wednesday followed by the third and final game on Sunday in Hambantota.
Teams:
Sri Lanka: Angelo Mathews (capt), Lahiru Thirimanne, Tillakaratne Dilshan, Kusal Perera, Kumar Sangakkara, Mahela Jayawardene, Ashan Priyanjan, Sachithra Senanayake, Ajantha Mendis, Nuwan Kulasekara, Lasith Malinga.
South Africa: AB de Villiers (capt), Hashim Amla, Quinton de Kock, Jean-Paul Duminy, Imran Tahir, Jacques Kallis, Ryan Mclaren, David Miller, Morne Morkel, Vernon Philander, Dale Steyn.
Umpires: Steve Davis (AUS), Ranmore Martinesz (SRI)
TV umpire: Nigel Llong (ENG)
Match referee: Jeff Crowe (NZL)