Somma and Pienaar seal South Africa victory
Steven Pienaar added a second on the stroke of half-time when he shot home from the edge of the box to score his first goal for his country in almost six years.
The hosts took early control of the game at Rustenburg's Royal Bafokeng Stadium when striker Somma, winning only his second cap, tapped in at the near post after a storming run down the right wing by Anele Ngcongca.
He was denied a second when he struck the upright but Pienaar, captaining the side after Aaron Mokoena was left on the bench, doubled the lead after a corner just before the break.
The hastily arranged game was South Africa's last warm-up match before their African Nations Cup qualifier against continental champions Egypt at the end of March.