CARLSBAD, Calif. (AP) -- Martina Hingis was rarely tested in an easy 6-2, 6-3 victory over Meilen Tu on Tuesday in the Acura Classic.
Hingis, the former No. 1, controlled the match with her groundstrokes and took control when she broke Tu's serve in the sixth and eighth games to capture the first set.
After missing most of the past three seasons with ankle and foot injuries, Hingis returned to the WTA Tour full-time this year and won her first tournament at Rome in May for her 41st career title.
Hingis is ranked 13th.
"Coming off a long layoff, it's never easy. You feel like you can train forever, but once you get in a match you feel rusty," said Hingis, a five-time Grand Slam winner. "I didn't play my best tennis, but it will come with matches. I know that I can play better than what I played today. But it was a solid performance."
Maria Sharapova, ranked No. 4, was pushed hard early before she rebounded to win 10 of the final 11 games in a 6-4, 6-1 second-round victory over fellow Russian Vasilisa Bardina.
Sharapova, who received a first-round bye as the second seed, trailed 4-2 in the first set before she won 14 of the next 19 points to take the first set. Bardina, who played aggressively in the first set, started making numerous unforced errors and held her serve just once in the second set.
Japan's Ai Sugiyama, the runner-up to Mary Pierce in last year's final, was bounced in the first round with a 6-1, 7-5 loss to Vera Zvonareva of Russia. The 13th-seeded Sugiyama played uncharacteristically flat in the first set before Zvonareva, ranked as high as No. 9 in the world in 2004, closed out the match.
Among other seeded players in first-round action, No. 10 Anna-Lena Groenefeld of Germany was upset by Elena Vesnina of Russia 3-6, 6-3, 6-3; 11th-seeded Daniela Hantuchova of Slovakia was winning easily over Kveta Peschke of the Czech Republic, 6-1, 4-0 when Peschke retired with an injury; and No. 15 Katarina Srebotnik of Slovenia defeated France's Marion Bartoli 6-3, 6-0.
The eighth-seeded Hingis received a first-round bye.
"Every match, every game, every time I go out there and win, it's a positive influence on what I'm going to do in the future," she said. "When (the court announcer) was talking all about my past and what I've achieved, it kind of reads like a fairy tale. It's one part of my life, then I was doing other things.
"Now I'm back here. I feel like a rookie more than a comeback."
In other first-round matches, wild-card entrant Ashley Harkleroad won 6-2, 6-3 over fellow American Jill Craybas; American qualifier Amy Frazier had a 6-3, 7-6 (7) victory against Tatiana Golovin of France; and Alona Bondarenko of the Ukraine defeated Ivana Lisak of Croatia 6-2, 7-6 (2) after Lisak replaced the injured Chanda Rubin.