World No. 2 Lindsay Davenport has pulled out of the China Open because of a strained back, organizers said Monday. Top players Maria Sharapova and Venus and Serena Williams were scheduled to compete later in the week. All three have first round byes, putting them directly into the second round. In first-round action Monday, Japan's Ai Sugiyama defeated her countrywoman Akiko Morigami 7-6 (3), 6-4.