Wimbledon runner-up Agnieszka Radwanska withdrew from the Italiacom Open citing respiratory problems, saying the humid weather in London affected her in Saturday's final loss to Serena Williams.
Radwanska, the first Polish player to reach a Grand Slam final since 1939, battled through the illness at the All England Club starting with Thursday's semifinal victory over Angelique Kerber.
In Monday's play, Irina-Camelia Begu of Romania beat Slovenia's Polona Hercog, last year's runner-up, with a 6-1, 7-6 (8) victory in the first round. Begu, ranked 10 spots behind the 63rd-ranked Hercog, saved three set points in the tiebreaker.
Earlier on the red clay courts at the Country Time Club, seventh-seeded Alize Cornet of France beat Mariana Duque-Marino of Colombia, 6-3, 6-2; Alexandra Cadantu of Romania eliminated Kiki Bertens of the Netherlands 6-3, 6-2; and Lourdes Dominguez Lino of Spain defeated Yulia Putintseva of Kazakhstan 6-2, 6-4.
French Open runner-up Sara Errani is the tournament's top seed.
