Springbok captain Victor Matfield paid tribute to his side's staunch defence as the world champions withstood a late rally from Wales to win 25-29 at the Millennium Stadium.
The victory kept South Africa's hopes of a Grand Slam alive after they brushed aside Ireland last weekend.
South Africa were 17-9 behind at the break but scored 17 unanswered points in the space of seven minutes to grab the initiative from Wales.
Wales refused to cave in and mounted a fierce late rally but couldn't breach the green wall.
"I'm very proud of the boys, they showed great character," said Matfield. "Wales put us under pressure and it was a great game for the spectators to watch.
"Well done to Wales, they really came out and played well. "(Defending) is something we really worked hard on (in training) and it came through and we were happy with that," he added.
Referring to a possible Grand Slam, Matfield said: "I don't know. There's still a fair way to go. We're focusing on Scotland and that's going to be another huge game. We will enjoy tonight and then start fresh from zero on Monday again."
As the countdown continues for RWC2015, Tournament Chief Executive Debbie Jevans visited the Millennium Stadium to discuss preparations for the eight matches and reveal the positive news that 100,000 tickets for games at the home of Welsh rugby have sold in the last seven days.
Jason Harries is targeting a first win on the World Series circuit this season with Wales. The series returns to action this weekend in Dubai where Harries is part of a team hoping to build from its efforts in round one in October.
Wales skipper Jevon Groves says his side have addressed a few points from Gold Coast and aim to 'hit the ground running' in the next two rounds of the World Series, kicking off with this weekend in Dubai before heading off to South Africa next week.
Wales Sevens manager Steff Thomas is hopeful his side can build from a quarter-final spot in the opening round of the World Series in Australia when his side take part in the forthcoming double header in Dubai and South Africa.