Key Biscayne - Fifth-seeded Angelique Kerber of Germany has eked out a victory in her opening match at the Sony Open, beating Peng Shuai of China 6-3, 1-6, 7-6 (5) on Thursday.
Kerber, a two-time Grand Slam semifinalist, matched her best showing at Key Biscayne by reaching the third round.
No. 12 Ana Ivanovic beat American Lauren Davis 6-1, 6-1, and No. 28 Svetlana Kuznetsova, the 2006 champion, lost to Croatian qualifier Donna Vekic 7-6 (5), 7-5.
Six-time champion Serena Williams and Maria Sharapova were scheduled to play their opening matches late Thursday. Seeded men begin play on Friday.
Results on Thursday from the third day of the WTA and ATP Miami Masters (x denotes seeded player):
Jack Sock (USA) bt Guido Pella (ARG) 6-3, 6-4
Denis Istomin (UZB) bt Nicolas Mahut (FRA) 7-6 (10/8), 7-6 (7/2)
Stephane Robert (FRA) bt Alex Bogomolov (RUS) 7-5, 6-4
Aljaz Bedene (SLO) bt Jimmy Wang (TPE) 1-6, 6-2, 6-4
Angelique Kerber (GER x5) bt Peng Shuai (CHN) 6-3, 1-6, 7-6 (7/5)
Tsvetana Pironkova (BUL) bt Sorana Cirstea (ROM x25) 6-3, 6-3
Ekaterina Makarova (RUS x23) bt Rebecca Peterson (SWE) 6-1, 6-1