Cape Town - The Williams sisters gave the United States a 2-0 lead over Argentina in their Fed Cup World Group II tie on Saturday.
Venus defeated Paula Ormaechea 6-3, 6-2, in the first match, and Serena, the newly crowned Australian Open champion, won over Maria Irigoyen 7-5, 6-0.
Serena can clinch the first-round tie on Sunday, in the first reverse singles against Ormaechea.
That should put the U.S. in the playoffs in April, for a chance to return to the World Group next year.
Argentina's only possible advantage was the clay surface, which is never a favorite of the Americans. The Williams sisters own 56 Grand Slam singles, doubles and mixed doubles titles. Ormaechea is world ranked No. 121, and Irigoyen No. 197.