Martina Hingis overwhelmed Amanda Coetzer 6-1, 6-0 before Wayne Ferreira pulled South Africa even by outlasting Roger Federer 6-3, 3-6, 6-3.
In the deciding mixed doubles, Switzerland beat South Africa 6-2, 6-3 as Coetzer lost her serve four times.
In another match Friday, Thailand beat Australia 2-0 to leave the host country winless in the tournament.
On Thursday, the U.S. team of Monica Seles and Jan-Michael Gambill, needing only one win to advance to the final, swept Belgium 3-0.
Hingis proved to be a formidable opponent for Coetzer, who managed to earn just three game points on serve in the entire match. They all came when Coetzer was already down 0-2 in the second set, but she failed to convert them and was unable to hold serve throughout the 47-minute rout.
Her only consolation came when she broke Hingis in the third game of the match, but in the next game, the South African became distracted by an overrule by umpire Jane Harvey that gave Hingis a 3-1 lead.
Coetzer thought a ball down the line from Hingis landed wide, but Harvey swiftly called the shot good as the linesman signaled the ball wide.
The normally mild-mannered Coetzer protested in vain, then dropped eight of the next nine points to leave Hingis ahead 5-1. In the second set, Hingis dropped just two points on serve.
Ferreira then withstood a strong challenge from Federer, recovering from dropping his serve in the opening game of the deciding set. Having lost his first two matches in the competition, the South African was far more focused than in his previous matches.
"I had a couple of lapses of concentration, but I still hit the ball very well," Ferreira said. "Roger missed a couple of first serves, so I put a little bit of pressure on his second serve."