SHENZHEN, China - World No.3 Naomi Osaka has withdrawn from the 2019 Shiseido WTA Finals Shenzhen due to a right shoulder injury. Osaka, who began her WTA Finals campaign with a 7-6(1), 4-6, 6-4 win over No.6 Petra Kvitova on Sunday, was set to play World No.1 Ashleigh Barty on Tuesday night. 

Osaka will be replaced by first alternate Kiki Bertens in the Red Group. 
 
“I’m disappointed to have to withdraw from the Finals,” Osaka said in a statement. “It has been a great event in Shenzhen, and it’s the biggest WTA event of the year. This is not how I wanted to end this tournament or my season. I look forward to getting healthy and hope to be back here in Shenzhen next year.”

The reigning Australian Open champion finishes the season on an 11-match win-streak, having gone undefeated since the US Open. She tallied back-to-back titles at the Toray Pan Pacific Open and China Open, and secured her first career-win at the WTA Finals against Kvitova. 

Osaka told reporters she injured her right shoulder during Beijing final three weeks ago, but hoped the injury would heal in time for the WTA Finals. "I didn't serve for a while when I was in Japan," Osaka told reporters in Shenzhen. "I just started serving, like, the last two days. Felt better, came here, then I played my match.

"I felt it immediately. When I woke up the day after, it was throbbing and stuff. Yeah, didn't serve at all yesterday."

Osaka said the shoulder issue was a recurring injury, but hoped it could be addressed with rest and rehabilitation.

"I injured my shoulder like five years ago or something, but not, like, heavy," Osaka said. "It was in Thailand when I was like 17 or something. It wasn't that big of a deal. I just had to rest it. I'm hoping it's more like that.

"It doesn't feel like it's anything more serious than muscular. I think if it was like bone-related then I wouldn't be able to lift it, but I am able to do that. It's just a little bit painful.

"Definitely I don't think it's something that I would immediately need surgery for. I've never gotten surgery, so I feel like I'm very lucky on that. I'm not really hoping that will change any time soon."

No.10 Bertens will replace Osaka in the Red Group to play World No.1 Barty on Tuesday night. The match will be a rematch of the China Open semifinals, where Barty saved match point to advance. A semifinalist in Singapore last year, Bertens still has the opportunity to advance out of the group into the semifinals. 

Here are the Red Group qualification scenarios heading into Day 3, where No.1 Barty faces Bertens, and No.6 Kvitova faces No.7 Bencic. 

- If Barty defeats Bertens tonight, she advances along with the winner of tonight's Bencic-Kvitova match. If Bencic defeats Kvitova, Barty will win the group, with Bencic second. If Kvitova defeats Bencic, the winner of Thursday's Kvitova-Barty match will win the group, and the loser will finish second. 

- If Bertens and Kvitova win tonight, Bencic is eliminated. Thursday's matches will determine which of the remaining three players advances from the Red Group. 

- If Bertens and Bencic win tonight, all four players have a chance to reach the semifinals, with Thursday's matches determining who advances from the Red Group 

The final round-robin group standings are determined by the greatest number of match wins followed by the greatest number of matches played. Therefore, if an alternate were to finish with an equal number of match wins but fewer matches played, the player with more matches played would finish ahead in the standings.