Russia's Vera Douchevina beat France's Emilie Loit 6-3 6-3 to earn a second round tie against defending champion Serena Williams at the Nasdaq-100 Open.
Williams is next up for Douchevina
Eleni Daniilidou beat Tathiana Garbin 6-3 4-6 6-1 and will now face number two seed Maria Sharapova.
Williams is going for a fourth consecutive title at Key Biscane.
In other matches American Marissa Irvin eliminated Spain's Magui Serna 6-3 7-5, while Meghann Shaughnessy of the USA beat Ukraine's Yuliana Fedak 6-3 6-0.
Nicole Pratt of Australia defeated Thailand's Tamarine Tanasugarn 6-3 6-2.