Lindsay Davenport advanced to the second round of the US Open with a 6-4 6-4 victory against 23-year-old Na Li of China at Flushing Meadows.
The American, ranked number one for most of the year, reclaimed the top spot after winning the Pilot Pen championship last weekend.
Also, Elena Dementieva was given a useful work-out as she booked her place in the second round beating Czech Lucie Safarova 7-5 6-3.
Third seed Amelie Mauresmo cruised to a comprehensive 6-3 6-2 victory over Roberta Vinci.
Mauresmo's fellow Frenchwoman Nathalie Dechy also progressed. The number 15 seed enjoyed a 6-4 7-5 win against Severine Beltrame.
Belgium's Justine Henin-Hardenne, seeded seventh, was in convincing form, winning 6-3 6-0 against Zuzana Ondraskova.
Jelena Jankovic (17) was another straight-sets winner against Denisa Chladkova, 7-5 6-3, while Elena Likhovtseva (19) easily overcame Tathiana Garbin, 6-4 6-1.
