Serbia's Ana Ivanovic advanced to the second round of the Qatar Open on Monday when Carla Suarez Navarro withdrew midway through their match because of a back injury.
Ivanovic, the 2008 French Open champion, was leading 6-1, 4-1. Trailing 1-2 in the second set, Suarez Navarro had already sought courtside treatment from the WTA Tour medical team. The Spaniard then briefly left the court before resuming the set.
"It is very unfortunate for her," Ivanovic said. "It is never enjoyable to win a match like that, but I hope she recovers fast. I am happy with the way I played in the match."
Two-time Grand Slam champion Svetlana Kuznetsova of Russia joined Ivanovic in the second round after a 7-5, 6-3 win over Maria Jose Martinez Sanchez of Spain.
After a slow start, the former French and U.S. Open champion breezed through the second set to set up a match against Jie Zheng of China or Maria Kirilenko of Russia.
"It was definitely a tough win for me," Kuznetsova said.
Ksenia Pervak of Kazakhstan rallied from a set down to beat 10th-seeded Anastasia Pavlyuchenkova of Russia 1-6, 6-2, 6-3. It was the 20-year-old Pervak's fourth win of the season.
China's Shuai Peng, seeded 14th, defeated qualifier Fatma Al Nabhani of Oman 6-0, 7-5. Israel's Shahar Peer blanked Moroccan wild card Nadia Lalami 6-0, 6-0.