SINGAPORE - World No. 1 Simona Halep has withdrawn from the BNP Paribas WTA Finals Singapore presented by SC Global due to a back injury.

The 27-year-old Romanian said in a statement on Thursday (Oct 18): "Unfortunately, after much discussion with my team and doctors, I have made the decision to withdraw from the WTA Finals in Singapore.

"I wanted to finish 2018 on a high after such an incredible year, but sadly my back injury hasn't healed the way we hoped it would and I need to put my long-term health first. I'm sad I won't be able to play the fifth and final edition here in Singapore, but I'm confident this is the right decision and will do everything I can to be back fighting for my place at the WTA Finals next year. Singapore is a special city and I'm sure the fans will enjoy seeing some fantastic women's tennis this week."

Halep, who won her maiden Grand Slam title at the French Open this year, had withdrawn from this week's Kremlin Cup in Moscow for the same reason.

Replacing her in the Oct 21-28 WTA Finals Singapore singles line-up is Kiki Bertens of the Netherlands, who reached the final in the doubles tournament here with Sweden's Johanna Larsson.

Said Bertens: "I'm very happy with my season and to finish it off at the WTA Finals is the ultimate prize.

"I have great memories in Singapore from reaching the doubles final last year. I look forward to being back to compete in front of the amazing crowd."