Naomi Osaka has withdrawn from the WTA Finals in Shenzhen.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."

Osaka brings the style again to beat Gasanova in Wimbledon second round
First-half goals send Mexico to comfortable 2-0 victory over Ecuador
Mbappe scores twice as France ease past Sweden 3-0 to reach last 16
Serena and Wawrinka go down fighting at Wimbledon
Norway edge Ivory Coast to advance at World Cup
