BEIJING, Oct. 4 (Xinhua) -- Simona Halep, the No.1 seed at China Open, was forced to pull out in the first round due to her ankle injury.

Halep became the top seed at China Open after the current world No.1 Serena Williams's withdrawal, but she was forced to retire in her opening match against Spanish qualifier Lara Arruabarrena when she was falling behind at 4-5 due to a left ankle injury.

Halep appeared in the news conference to talk about her injury after the match. "I have pain in my Achilles. It's getting worse," the World No.2 said. "I thought that it was getting better and I could play, but no - I don't want to force it. And it's a tough injury because it's always dangerous to continue with the tendon, so, I hope to just recover and be healthy again soon."

The Romanian hopes to recover for the BNP Paribas WTA Finals Singapore presented by SC Global. "I hope I can play. It was my goal this year. I will see - I need treatment and a break, for sure."

Arruabarrena will meet Bethanie Mattek-Sands in the second round, who beat Alize Cornet, 6-3, 6-3.