Sabine Lisicki hit the fastest record serve on the WTA tour but it wasn't enough in the first round of the Bank of the West Classic where fifth-seeded Ana Ivanovic got the better of the German 7-6, 6-1.
Experienced duo Venus Williams and Daniela Hantuchova also won, while defending champion Dominika Cibulkova was beaten 6-2, 4-6, 6-2 by Garbine Muguruza of Spain.
Lisicki blasted a serve of 131 mph (211 kph) at 5-5. The serve eclipsed Venus Williams' record of 129 mph (208 kph) in 2007.
Ivanovic took full advantage of Lisicki's weak second serve, winning 16 of 23 points, and though she had 10 break points against her, the Serb saved eight of them, while Lisicki was broken four times from just five opportunities.
"Sometimes just a few points make a difference and it helps to be positive in a tight situation,'' Ivanovic said. "I did that today in the tiebreak.''
Ivanovic is playing her first tournament since hiring Dejan Petrovic as coach, replacing Nemanja Kontic.
The Serbian next faces Canadian qualifier Carol Zhao, who was leading Yanina Wickmayer, 6-2, 1-0, when the Belgian retired because of a viral infection.
Williams beat Polish qualifier Paula Kania 6-3, 6-2, and next plays fourth-seeded Victoria Azarenka, whom she has beaten in three previous meetings.