Seppi knocked out at Winston-Salem

American Mardy Fish retires with heat stroke during third set at Winston-Salem Open.

Andreas Seppi was upset Tuesday night in the second round of the Winston-Salem Open, leaving Spaniard Tommy Robredo as the only survivor among the top four seeds at the tournament.

Second-seeded Seppi was beaten by American qualifier Steve Johnson 6-7 (5), 6-4, 7-5.

The tournament lost two of its top three seeds Monday when No. 1 Tomas Berdych and No. 3 John Isner, the two-time defending champion, withdrew with injuries.

Fourth-seeded Robredo beat France's Guillaume Rufin 7-6 (5), 4-6, 6-3 to advance.

Eighth-seeded Juan Monaco of Argentina defeated France's Nicolas Mahut 6-7 (4), 6-3, 6-4 in the hardcourt tuneup for next week's US Open.

Mardy Fish retired in the third set of his match with No. 11-seeded Jarkko Nieminen, who was leading 7-5, 6-7 (3), 3-2 when his American rival quit because of heat stroke.

Fish said in a statement he developed "heat stroke" and the "very hot and humid" weather made it difficult to continue the match.

In other second-round matches, fifth-seeded Benoit Paire of France beat American James Blake 7-6 (9), 2-6, 6-3; seventh-seeded Fernando Verdasco of Germany beat American Tim Symczek 3-6, 6-3, 6-3; ninth-seeded Jurgen Melzer of Austria beat qualifier Thiemo de Bakker 7-5, 6-7 (4), 4-2; and 13th-seeded Dmitry Tursunov of Russia defeated qualifier David Goffin of Germany 4-6, 7-5, 6-1.