Paris: French Open champion Li Na of China was forced to quit her first-round match at the WTA Paris Indoor Open.
Third-seeded Li withdrew while trailing Bulgarian Tsvetana Pironkova 6-7, 2-3 at the Paris-Coubertin Stadium Tuesday.
Li was visibly suffering with a back problem and finally abandoned the match after receiving treatment courtside, Xinhua reported.
Earlier, Serbia`s Jelena Jankovic, the fourth seed, withdrew after failing to recover from a left thigh injury she picked up during her win over Belgium Kirsten Flipkens in Serbia`s Fed Cup World Group first round success last weekend.
Germany`s Mona Barthel reached the second round after beating Barbora Zahlavova Strycova of the Czech Republic 6-3, 6-2 with another Czech Petra Cetkovska easing past Italy`s Alberta Brianti 6-3, 6-3.