SYDNEY, Australia -- Martina Hingis and Serena Williams won their season debuts Tuesday, and Paradorn Srichaphan of Thailand upset top-seeded Sebastien Grosjean of France 6-3, 6-4 at the Adidas International.

Hingis, the defending champion, needed just 46 minutes to beat Lisa Raymond 6-1, 6-1 in this Australian Open tuneup. But she "felt a little wonky" on her return from an ankle injury.

Hingis tore ligaments in her right ankle during a match in Germany in October and lost her No. 1 ranking after 73 consecutive weeks.

Williams, seeded fourth, opened the year with a 6-2, 4-6, 6-3 win over Russia's Anna Kournikova. Williams is seeded fourth.

"I put pressure on myself," she said. "I am practicing well -- in practice I'm a totally different person. I think my mind and my feet and my head was not into it."

But Williams, the U.S. Open champion in 1999 and a finalist last year, said she was feeling upbeat about next week's opening Grand slam event.

Hingis saved four break points and said it was a three-month layoff rather than any ankle trouble that gave Raymond the opportunities.

"I felt a little nervous and didn't really know what to expect from her," Hingis said. "I think it is a great start to the new season, especially since I hadn't played in so long.

"It's always nice to come back to a place where you have had success in the past. It gives you a little extra kick, a little bit more confidence. "

Hingis won this tournament last year and in 1997 and also won the Australian Open three consecutive years (1997-99).

Paradorn, ranked No. 112, served an ace on his first match point and dropped to his knees and kissed center court after beating Grosjean.

Paradorn qualified for the Sydney event by reaching his first final last week at the TATA Open in India, where he lost in straight sets to Guillermo Canas of Argentina.

His biggest previous win was against Magnus Norman at Singapore in 1999, when the Swede was ranked No. 3. In December, he earned a wild card for the Australian Open by winning the Asian Championship.

Paradorn won the first set Tuesday in 31 minutes. He broke Grosjean again early in the second set and then, at 5-4, served out at love.

"I had nothing to lose against Grosjean and I can play whatever I want," he said. "I just try my best and show how good I am."

In other first-round matches, second-seeded Roger Federer of Switzerland edged Spanish Hopman Cup hero Tommy Robredo 7-6 (5), 7-6 (5) in the final match on center court.

Julien Boutter of France upset sixth-seeded Thomas Johansson of Sweden 7-6 (4), 7-5, and Rainer Schuettler beat Nicolas Kiefer 6-2, 6-2 in an all-German match.

Karol Kucera of Slovakia beat Fabrice Santoro of France 6-4, 1-6, 6-3, and Bohdan Ulihrach of the Czech Republic defeated Nicolas Lapentti of Ecuador 6-3, 6-1.

Hicham Arazi withdrew from his match against Belgium's Xavier Malisse after losing the first set. The Moroccan was treated for a blistered left hand while trailing 4-3 and left the court after losing the set 6-3.

In other women's matches, Wimbledon finalist Justine Henin, seeded fifth, beat Austria's Barbara Schett 7-6 (3), 6-3 and sixth-seeded Amelie Mauresmo of France defeated Amanda Coetzer of South Africa 6-3, 5-7, 6-3.