Gaudio, the 2004 French Open champion, defeated French crowd favorite Arnaud Clement, the 2000 Lyon winner and 2003 runner-up, 6-3, 4-6, 6-3. Ancic beat American James Blake 6-2, 7-6 (7-5). Blake won in Stockholm just two weeks ago.
In one other Day-1 bout, Serb Novak Djokovic defeated Brazilian Ricardo Mello 7-6 (7-5), 6-4.
This week's top seeds are Wimbledon runner-up Andy Roddick of the United States and French Open finalist Mariano Puerta of Argentina.
Notable deaths of 2014 [PHOTOS]