STUTTGART, Germany, April 25 (UPI) -- Maria Sharapova and Caroline Wozniacki both advanced Wednesday when their opponents retired at the Porsche Tennis Grand Prix in Germany.
Sharapova, No. 2 in the world, built a 6-3, 1-0 lead over Alize Cornet when Cornet suffered a right shoulder injury and was unable to continue. That put Sharapova into the third round.
Wozniacki, seeded sixth and playing a first-round match, was up by the same 6-3, 1-0 score against Jelena Jankovic when Jankovic stopped because of a lower back injury.
Fourth-seeded Agnieszka Radwanska swept through a 6-3, 6-4 win over Greta Arn in a second-round match. Radwanska lost her serve once in each set but still won two-thirds of the points when serving.
Other first-round results Wednesday saw Mona Barthel edge past Ana Ivanovic 7-5, 7-6 (7-4), while Akgul Amanmuradova had 11 aces in a 6-2, 5-7, 6-3 victory over Dominika Cibulkova.