Andy Roddick reached the fourth round of the Sony Ericsson Open on Sunday after overcoming two set points in the tiebreaker to beat Dmitry Tursunov of Russia 7-6 (9), 6-2.

The fifth-seeded Roddick erased one set point with an ace and the second when Tursunov netted a forehand, and won the final three points in a gruelling 75-minute first set. Roddick finished with 11 aces and faced only one break point.

Second-seeded Roger Federer also won, beating Nicolas Kiefer for the 11th consecutive time, 6-4, 6-1.

There were two upsets on the women’s side, both involving last year’s French Open finalists. Seventh-seeded Ana Ivanovic, the defending Roland Garros champion, lost to No. 25 Agnes Szavay 6-4, 4-6, 6-1. No. 2 Dinara Safina was beaten by unseeded Samantha Stosur 6-1, 6-4.

No. 5 Venus Williams, seeking her fourth Key Biscayne title and her first since 2001, beat Anna-Lena Groenefeld

7-5, 6-3. Also, No. 4 Elena Dementieva beat No. 31 Carla Suarez Navarro 6-2, 6-2, and former US Open champion Svetlana Kuznetsova defeated Nicole Vaidisova 6-1, 6-4.

Only two US women made the round of 32 – five-time champion Serena Williams and big sister Venus