Tennis John Isner jolted Roger Federer with his big serve and booming groundstrokes, winning, 4-6, 6-3, 7-6 (7-4), 6-2, to give the United States a 2-0 lead against Switzerland in the first round of the Davis Cup yesterday in Fribourg, Switzerland. In opening singles, Mardy Fish outlasting Stanislas Wawrinka, 6-2, 4-6, 4-6, 6-1, 9-7. The US can sweep Switzerland in the best-of-five series today when Mike Bryan and Ryan Harrison face Federer and Wawrinka in doubles . . . Top-seeded Maria Sharapova was ousted from the quarterfinals of Open GDF Suez in Paris, beaten by Angelique Kerber, 6-4, 6-4.