French Open champion Li Na of China and Serbia’s Jelena Jankovic were both forced to withdraw from the WTA Paris Indoor Open because of injuries.

Third-seeded Li withdrew while trailing Bulgarian Tsvetana Pironkova 7-6 (7/5), 3-2 in their first round tie at the Paris-Coubertin Stadium on Tuesday.

Li was visibly suffering with a back problem and finally called it a day after receiving treatment courtside.

“I hurt myself in the Fed Cup at the weekend,” explained Li.

“It had gotten better since and this morning it didn’t hurt. But the stab of pain returned, very strong and I couldn’t continue.

“I don’t know if it’s because of the Fed Cup, maybe I’m getting old as well,” added Li, who turns 30 later this month.

Earlier world number 13 Jankovic, the fourth seed, withdrew after failing to recover from a left thigh injury she picked up during her win over Belgian Kirsten Flipkens in Serbia’s Fed Cup World Group first round success last weekend.

“I had hoped that after treatment I could still play here but unfortunately it’s impossible,” said Jankovic. “Australia (Open) and the Fed Cup and then here, that’s a lot. But it’s important for me to play for my country.”

Russia’s Maria Sharapova, the Australian Open finalist, and France’s Marion Bartoli, are the big names remaining in the tournament and open their campaigns in the second round midweek.

Germany’s Mona Barthel advanced to the second round after beating Barbora Zahlavova Strycova of the Czech Republic 6-3, 6-2 with another Czech Petra Cetkovska advancing past Italy’s Alberta Brianti 6-3, 6-3.