Simona Halep hopes to be fit to compete in the WTA Finals later this month after retiring from her opening match at the China Open on Sunday.

A recurring Achilles injury saw Halep call a halt to her encounter with Lara Arruabarrena with the Spaniard 5-4 ahead in the first set.

Halep is set to be the top seed in Singapore after world number one Serena Williams revealed her 2015 season had come to a premature end.

However, the Romanian now faces a battle to regain full fitness.

"I have pain in my Achilles. It's getting worse," said Halep.

"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.

"I felt it a little bit in Guangzhou, a little bit in Wuhan, and here was the worst.

"That's why I stopped today. I didn't think it would become like this. I don't feel well with my tendon right now.

"My first thought is to be healthy, and of course every tournament is important, but the most important thing is to be okay, to feel no pain, and then I will see.

"I hope I can play [in the WTA Finals]. It was my goal this year. I will see - I need treatment and a break, for sure."