South Africa crushed Uganda 18-0 on the first day of the Baseball Africa Cup in front of a home crowd in Johannesburg.
Their dominant victory at the Boksburg City Stadium was preceded by Zimbabwe's 11-5 defeat of Burkina Faso.
The four teams are the only sides left in the competition after Nigeria and Kenya withdrew.
South Africa is the only African nation included in the World Baseball and Softball Confederation (WBSC) world rankings and are ranked at number 23.
Tomorrow, Zimbabwe play Uganda while South Africa face Burkina Faso.
After a final set of matches on Friday (May 3), the semi-finals will take place on Saturday (May 4) and the final on Sunday (May 5).
The winner will be given a place at the WBSC Baseball Europe-Africa qualifying event for the Tokyo 2020 Olympic Games, taking place in Italy from September 18 to 22.
Baseball is returning to the Olympics in 2020 after a 12-year hiatus.