Naomi Osaka has withdrawn from the WTA Finals in Shenzhen.
The world number three from Japan picked up a shoulder injury after beating Petra Kvitova in three sets in her opening match on Sunday.
She'll now be replaced by alternate Kiki Bertens.
"I look forward to getting healthy and hope to be back here in Shenzhen next year," said Osaka.
"I'm disappointed to have to withdraw. This is not how I wanted to end this tournament or my season."