The second set was much more interesting with five breaks of serve alltogether. Roddick saved a setpoint with Dimitrov serving for the set at 5-4 and managed to win three games in a row, breaking Dimitrov’s serve to love to close out the match.
Roddick’s next opponent will be seventh seed Nicolas Almagro of Spain, who defeated his fellow countryman Tommy Robredo 7-5, 6-3.
The 18 year old Australian Bernard Tomic upset the American Mardy Fish, winning 4-6, 6-1, 6-4.
World no.49 Tomic lost to Fish at the Japan Open last week but this time managed to turn the match around to celebrate only his second win against top 10 players.
In other second round matches, Florian Mayer of Germany ousted former world no.3 David Nalbandian of Argentina 6-3, 6-4, the Swiss Stanislas Wawrinka eliminated the qualifier Donald Young 6-7 (5), 7-6 (2), 6-2 and Gilles Simon of France dismissed Albert Montanes of Spain 6-1, 6-1.