STRASBOURG, France (AP) — Defending champion Caroline Garcia advanced to the second round of the Strasbourg International by beating Jennifer Brady 6-3, 6-4 while top-seeded Caroline Wozniacki retired injured from her match on Monday.

Wozniacki, a former world No. 1 ranked 12th, trailed Shelby Rogers of the U.S. 7-6 (8), 1-0 when she called it quits because of back pain, six days before the French Open.

"I came back and had my chances to win that first set, and then I started feeling my back," Wozniacki said. "I felt it kind of in the middle of the first set. At this point, it's importtant for me to try and get ready for the French Open and be 100 percent for that."

After a good start to the season punctuated by runner-up positions in Doha, Dubai, and Miami, Wozniacki has been struggling on the European clay, suffering early losses in Prague and Madrid. She withdrew from the French Open last year because of an injured right ankle.

Rogers, who made it to the quarterfinals at Roland Garros last year, saved three set points before taking the opener.

The 29th-ranked Garcia broke early in the opening set but struggled wih unforced errors in the second against her American opponent. The Frenchwoman found her rhythm toward the end of the second set and won three games in a row to progress at the tune-up tournament for Roland Garros.

The fifth-seeded Garcia won her first title in more than two years in Strasbourg last year.

Two other Frenchwomen lost. Wild card Alize Cornet was beaten by Peng Shuai 3-6, 7-5, 6-1 and Pauline Parmentier was defeated by Madison Brengle 6-1, 4-6, 7-6 (4).