Jennifer Rosales and Dorothy Delasin of the Philippines shot a 4-under 68 and the teams were tied at 11-under 133 after foursome play at the Gary Player Country Club.
Only third-place Taiwan (69) and Wales (71) beat par on the 6,466-yard course. Canada (73) was fourth and the U.S. team of Juli Inkster and Pat Hurst (76) fell to 10th with Brazil and Scotland.
The Korean pair of Ji-Yai Shin and Eun-Hee Ji held a comfortable lead at 14 under until posting a 7 when their tee shot got caught in thick rough in the hazard.
'We'll just have to leave today's score behind us,' said Shin, whose second shot only advanced the ball a few inches, and Ji opted to take a penalty drop. Three putts spoiled what had been a round with just one bogey.
The Americans entered the round tied for fourth in the two-player team event that features 20 countries.
'We didn't play very well,' Inkster said. 'I didn't drive the ball very well. We just never really got it into a rhythm and this is the type of format where you need to get into a rhythm.'
The Philippine pair got their first birdie on the eighth hole, and dropped a shot on the 13th. They finished with three straight birdies.
'But all along we played really well,' Delasin said. 'We were only in the rough twice and that helped us shoot a good score.'
France, in second place after the opening round, was tied for fifth with Wales and Japan. Gwladys Nocera and Virginie Lagoutte-Clement shot 76. Maria Hjorth and Sophie Gustafson of Sweden had a 77 to slide into a share of 13th with China.
Host South Africa shot 72 for ninth, a stroke behind defending champion Paraguay.
The final round Sunday will be best ball.