Top seed Amelie Mauresmo of France rallied from a set and a break down to reach the third round of the Nasdaq-100 Open in Miami.
Mauresmo needed just over two hours to beat 18-year-old Russian Maria Kirilenko 4-6 6-4 6-1.
The players needed to invoke the WTA Tour's heat rule which allowed them a 10-minute break before the third set.
Unseeded Kim Clijsters kept up her hot streak by overcoming American Amy Frazier 6-2 6-3.
The former world number one, playing her third event since missing most of 2004 with a wrist injury, has lost only one of her 12 matches since launching her comeback last month.
The 25-year-old Mauresmo, ranked second in the world, put her slow start down to a lack of rhythm as well as solid play from her young opponent.
"She played really well that first set," Mauresmo said. "But I thought I was giving her too many free points.
"I finally got my game together in the second set."
Two other Frenchwomen joined Mauresmo in the next round: Stephanie Cohen-Aloro defeating Slovakian Daniela Hantuchova 7-6 6-2, and Tatiana Golovin beating American Angela Haynes 6-0 6-7 6-3.