Champion Serena marches on

Williams was spurred on by her home Californian crowd

Serena Williams and Martina Hingis moved into the third round of the estyle.com Classic in California with straight sets victories.

Defending champion Williams, playing her first competitive match since Wimbledon, displayed signs of rustiness in her 7-5 6-3 victory over fellow American Jennifer Hopkins.

And world number one Hingis was made to work hard for her 6-2 7-5 win over Lilia Osterloh at the Manhattan Beach Country Club, Los Angeles.

We have a little respect for each other

  Martina Hingis on Lilia Osterloh

Williams, who beat Lindsay Davenport in last year's final, admitted she was not playing to her best, but was relieved to get back on the court after injury.

"I think maybe I was too excited and nervous at the beginning, because I was playing in front of my hometown," said Williams, who grew up in Compton, a 15-minute bus ride away.

"I didn't attack, and I didn't move very good. I was hitting every ball to her. I've been working really, really hard - it feels good to be out there.

"She's a good player. I won here the last two years and I'd like to keep it up. It's important to work toward the US Open."

Meanwhile, Osterloh, who lost to Hingis in the second round of the Acura Classic last week, was close to pushing the 20-year-old the distance when she served for the second set.

But the "Swiss Miss" countered to snatch the last three games with an impressive array of groundstrokes from the back of the court.

Martina Hingis shows her frustrations on court

"We have a little respect for each other," said Hingis, who is spending her 200th week as world number one.

"I was more concentrated in the first set, then we kept breaking each other.

"We got new balls at 5-4. Then she started missing a few. It was a good match. I really wanted it."

Elsewhere, sixth-seed Monica Seles beat fellow American Marissa Irvin, 6-3 6-2, while fifth-seed Nathalie Tauziat beat Thailand's Tamarine Tanasugarn of Thailand 6-3 7-6.

There was success for France's Sandrine Testud, who defeated Anne Kremer of Luxembourg 6-2 6-3 and Wynne Prakusya, who beat Italy's Rita Grande 7-6 6-2.

Prakusya, from Indonesia, replaced the injured Russian Anna Kournikova in the main draw.