Martina Hingis opened defense of her title at the $535,000 tournament in Carlsbad by turning back Dominique Van Roost 6-2, 7-6 (7-2) on Tuesday to book a spot in the quarterfinals.

Hingis took a three-week break from the WTA Tour and returned to her Saddlebrook, Fla., home after her Wimbledon elimination by eventual champion Venus Williams last month. Top-seeded here, the 19-year-old showed little rust in her well-rounded game while improving to 4-1 lifetime over the Belgian star with a one hour, 29 minute victory. In other first-round matches, seventh seeded Anke Huber of Germany became the first upset casualty when American Amy Frazier ran off the first nine games en route to a 6-0, 7-6 (7-3) victory. Fifth-seeded Spaniard Conchita Martinez, the 1995 titleholder here, needed six match points before ousting stubborn Kim Clijsters of Belgium 6-3, 6-4. Sixth seed Nathalie Tauziat of France dismissed qualifier Anne Kremer of Luxembourg 6-4, 6-3 and eighth seed Sandrine Testud of France rallied past American Chanda Rubin 3-6, 7-5, 6-2. Completing first-round play in a night match of celebrity non-seeds, Anna Kournikova of Russia powered past hard-hitting Alexandra Stevenson 6-2, 6-3 in just 61 minutes.