Victoria Azarenka and Angelique Kerber were big-name casualties in the first round of the French Open on Tuesday, but defending champion Serena Williams eased through.
Azarenka has looked capable of adding to her two grand slam titles this year, but the No. 5 seed will not achieve that feat at Roland Garros after retiring with a knee injury when trailing 3-6, 7-6 (8-6), 0-4 against Karin Knapp. Kerber won her first grand slam title at the Australian Open in January, but fell at the first hurdle in Paris when Kiki Bertens beat the No. 3 seed 6-2, 3-6, 6-3 on Court Philippe Chatrier.