Buenos Aires, Argentina (SportsNetwork.com) - Venus Williams defeated Maria Irigoyen of Argentina on Sunday to advance the United States to the Fed Cup playoffs in April.

Williams' 6-1, 6-4 victory gave the United States an unassailable 3-1 lead in the best-of-five World Group II tie.

Paula Ormaechea had kept the Argentines in the tie by defeating Coco Vandeweghe 6-4, 6-4. Vandeweghe filled in for Serena Williams, who did not play because of illness.

The American duo of Taylor Townsend and Vandeweghe later made it 4-1 as they took down Tatiana Bua and Nadia Podoroska 6-2, 6-3.

Venus and Serena gave the United States a 2-0 lead on Saturday, defeating Ormaechea and Irigoyen.

The 17-time champion Americans must win another series in April to return to the top group next year.