CHARLESTON, April 20: An impatient Serena Williams squandered a match point before being stunned by unseeded Swiss player Patty Schnyder 2-6 6-4 7-5 in the quarter-finals of the Family Circle Cup on Friday.

In contrast to Williams’ rocky performance, defending champion and top seed Jennifer Capriati booked a semifinal showdown with Schnyder by easing past Anastasia Myskina of Russia 6-0 7-5.

The third-seeded Williams had a chance to close out the match at 5-4 in the final set with her opponent serving at 30-40, but Schnyder executed a backhand winner to get herself out of trouble.

The 30th-ranked Schnyder is attempting to regain the form that gave her five tournament titles in 1998 and a world ranking as high as number eight in early 1999.

This week is proving to be beneficial to the 23-year-old Schnyder’s confidence as she not only upset Williams, but also saw off sixth seed Amelie Maruesmo in a three-set second round encounter.

Capriati sailed through the first set in just 17 minutes as she overwhelmed Myskina with a mixture of power and finesse.

Results: (U.S. unless stated, prefix denotes seeding)

(Quarterfinals) Iva Majoli (Croatia) beat 13-Amanda Coetzer (South Africa) 6-3 7-5; 1-Jennifer Capriati beat Anastasia Myskina (Russia) 6-0 7-5; Patty Schnyder (Switzerland) beat 3-Serena Williams 2-6 6-4 7-5; 7-Sandrine Testud (France) beat Stephanie Foretz (France) 6-7 (4-7) 6-3 6-3.—Reuters