Justine Henin-Hardenne beat America's Abigail Spears in the second round of the Nasdaq-100 Open, her first match after a six-month injury lay-off.
Henin-Hardenne, sidelined since the US Open by a virus and knee injury, won 6-4 6-3 in the Miami heat.
Meanwhile, three-time champion Venus Williams, seeking her first title since last July, beat Anna-Lena Groenefeld of Germany 6-2 6-0.
And second-seed Maria Sharapova beat Eleni Daniilidou of Greece 6-0 6-4.
Meanwhile, number three seed Serena Williams claimed a 6-3 6-0 victory over Russian Vera Douchevina in 61 minutes.
Williams now faces 17-year-old Israeli qualifier Shahar Peer, a 2-6 6-4 7-5 winner over France's Marion Bartoli.
Ninth-seeded Vera Zvonareva of Russia fell to Spain's Nuria Llagostera Vives 3-6 6-3 6-1.