Ana Ivanovic started her quest for a third Generali Ladies title by defeating Yanina Wickmayer of Belgium 6-2, 6-4, while second-seeded Sloane Stephens overcame a slow start to beat Magdalena Rybarikova of Slovakia 6-3, 6-1 in the first round on Tuesday.
The third-seeded Ivanovic, who won the event in 2008 and 2010, served five aces and broke Wickmayer, the 2009 winner, five times.
Ivanovic next plays another former French Open champion, Francesca Schiavone of Italy.
Stephens dropped her first two service games, but the 12th-ranked American broke Rybarikova three times to take the opening set.
Stephens, who had lost her only previous match against Rybarikova, held serve throughout the second set for a convincing victory.
The American will next face Andrea Petkovic. The German led 5-2 in the second set against Yvonne Meusburger of Austria, but was broken twice while serving for the match before wrapping up a 6-3, 7-5 victory.
Earlier, Camila Giorgi of Italy upset last year’s finalist Julia Goerges of Germany 6-2, 6-3.
The 105th-ranked Giorgi, who won three qualifying matches to reach the main draw, avoided break points and converted the second match point on her serve.
In the second round, Giorgi faces fifth-seeded Kirsten Flipkens of Belgium, who rallied to beat 17-year-old Donna Vekic of Croatia 2-6, 6-2, 6-2.
Austria’s Patricia Mayr-Achleitner, who entered on a wild-card, came back from a set down to defeat sixth-seeded Sorana Cirstea of Romania 1-6, 6-3, 6-4.
Also, seeded players Carla Suarez Navarro of Spain and Dominika Cibulkova of Slovakia reached the second round. No. 4 Suarez Navarro defeated Kristyna Pliskova of the Czech Republic 6-2, 6-3, and No. 7 Cibulkova came from behind to beat Annika Beck of Germany 3-6, 6-2, 6-1.
Cibulkova next plays Katarzyna Piter of Poland, who defeated Irina-Camelia Begu of Romania 6-2, 4-6, 6-3.