Top seeds survive challenge in Miami

No one comes from behind to win quite like Sara Errani and Roberta Vinci. Today in Miami, the top seeds faced problems in their opening round against Kimiko Date-Krumm and Casey Dellacqua. Date-Krumm and Dellacqua won the first set in a tiebreak, Errani and Vinci won the second set 6-2, but they fell behind 4-6, then 5-7, in the tiebreak set. They wound up winning that tiebreak 11-9, and advanced to the second round.

The 2nd seeds, Andrea Hlavackova and Lucie Hradecka, didn't have the same fortune. They were beaten 6-4, 7-5 by Svetlana Kuznetsova and Flavia Pennetta.

The humidity went as high as 87% in Miami today, and that did not foretell a good outcome for Petra Kvitova, whose asthma flares in humid weather. There was also a heat break taken during Kvitova's third round match, and the Czech player looked as though she was barely able to withstand the conditions. It certainly didn't help that her opponent was the clever and ever-improving Kirsten Flipkens, who defeated Kvitova 6-0, 4-6, 6-1. There's really nothing more to say other than "Oh, Petra."

Venus Williams, suffering with a lower back injury, gave Sloane Stephens a walkover in the third round, and defending champion Agnieszka Radwanska had to go three sets against Magdalena Rybarikova. Garbine Muguruza beat Caroline Wozniacki 6-2, 6-4. Given the Dane's good performance in Indian Wells, who saw that coming?

Tomorrow, 6th seed Angelique Kerber faces the sometimes-dangerous Sorana Cirstea. For me (if I can find a way to watch it), the match of the day will be Roberta Vinci vs. Carla Suarez Navarro.