Sania Mirza and South African partner Liezel Huber, who made it to the doubles quarterfinals of the Acura Classic last week, crashed out in the first round of the Los Angeles Open on Monday night.
Sania and Huber lost to wild card entrants Ana Ivanovic (Serbia and Montenegro) and Maria Kirilenko (Russia) 7-6(2), 6-2.
The Indian ace also faces a tough first round in singles, as she takes on Jelena Jankovic on Tuesday night.
Serena Williams, close to full fitness after being sidelined for most of the year, returns to action at the tournament in Los Angeles with a sharpened appetite to win more titles. Williams, who became the fifth woman to hold all four Grand Slam titles at once with her victory at the 2003 Australian Open, takes on Russian 11th seed Maria Kirilenko in Tuesday's first round.
The former world number one, playing her second tournament in seven months because of a chronic knee injury, has also set her sights on regaining a top-100 ranking after slipping to 110.
"It's been awfully weird this year, not being able to play most of the year and especially missing out on two grand slams," American Williams told reporters on Monday.
"That was very difficult for me. But I've been training for the last few months and I look forward to getting more matches in and playing out the rest of the year.
"It's all about being here and playing, doing the best I can do, always thinking positive and just taking it one match at a time."
Williams has not competed since losing to Russian Vera Zvonareva in the semi-finals of the Cincinnati Open last month, her first tournament since the Australian Open in January.
She had planned to return at last week's Acura Classic in San Diego but withdrew on the advice of her doctor.