Top-ranked Maruesmo faces Kristina Barrois and number-two Sharapova meets Michaella Krajicek. On the men's side, second-ranked Rafael Nadal goes against Mark Philippoussis and James Blake takes on Juan Monaco.
Andre Agassi's tennis career has been extended for at least one more match. The 36-year-old Agassi has advanced to the second round by surviving a 6-7, 7-6, 7-6, 6-2 victory over Andrei Pavel in three-and-a-half hours Monday night. Agassi fell behind 4-0 in the third set before winning the next five games.
Also winning was 1998 champ Lindsay Davenport, who pounded out a 6-1, 6-4 victory over Klara Zakopalova. Davenport is playing with a sore shoulder that forced her to withdraw from Saturday's title match at the Pilot Pen tuneup event.
Fourth seed Elena Dementieva won, as did sixth seed Svetlana Kuznetsova and number-seven Patty Schnyder.
Number-15 Anna-Lena Groenefeld was the highest women's seed to lose.
The day's biggest upset belongs to Feliciano Lopez, who knocked off men's third seed Ivan Ljubicic. Number-19 Dominik Hrbaty also lost.
Billie Jean King was honored at the stadium before the night session began. The tournament grounds were officially renamed the Billie Jean King National Tennis Center in honor of King, the only woman to win U.S. singles titles on all four surfaces.