Sofia Kenin, Belinda Bencic and Elise Mertens were all beaten at the Volvo Car Open, where Ash Barty moved through.
Madison Keys bersedia menguji Mari Sakkari dalam pusingan kedua selepas kembali beraksi dalam Kejohanan Jelajah WTA sejak September lalu dengan meraih kemenangan selesa dalam Terbuka Qatar.
Madison Keys had not played on tour since September, but the American looked in good shape as she began her season in Doha.
American Madison Keys is self-isolating just a few weeks before she was due to compete in the Australian Open.
Tsvetana Pironkova will get another chance to upset Serena Williams at a grand slam after both triumphed in Paris on Monday.
While Serena Williams and Sofia Kenin progressed, Garbine Muguruza crashed out on Thursday.
After being pushed at the Western & Southern Open, Serena Williams and Naomi Osaka reached the last 16.
Coco Gauff claimed another famous scalp in defending champion Naomi Osaka, as Serena Williams also suffered a shock defeat.
It was a good day for the favourites in the women's draw at the Australian Open, with Ash Barty and Serena Williams winning through.
Four women's singles seeds exited the Australian Open at the first hurdle, but Simona Halep and Karolina Pliskova did reach the next round.