HONG KONG (AFP) - Caroline Wozniacki lamented her "shitty" recent few months on Thursday after an unlucky incident involving a bread knife brought her season to an abrupt halt.
The former world No. 1 was trailing Svetlana Kuznetsova 7-5, 2-2 at the WTA Elite Trophy in Zhuhai, southern China, when she retired and later withdrew from the tournament.
According to the WTA Insider Twitter account, Wozniacki cut her finger badly with a bread knife from room service and was unable to hold her racquet properly, prompting the wrist injury.
"It's been a really, really frustrating, shitty second half of the year. Basically just been falling apart physically," she was quoted as saying by the WTA-linked account.
Denmark's Wozniacki, 25, won in Malaysia during a positive start to the season but highlights have become few and far between as the year unfolded.
She isn't the only star to fall foul of room service this week - coincidentally her former fiance, golfer Rory McIlroy, went down with food poisoning from a club sandwich in Shanghai.
Wozniacki's withdrawal could also affect Kuznetsova's chances of qualifying from Group D, as she was relying on the world No. 17 beating Roberta Vinci on Friday.
In Wozniacki's absence, Italy's Vinci will play alternate Anna Karolina Schmiedlova, the world No. 28 from Slovakia.
Earlier Venus Williams came from a set down against Chinese number one Zheng Saisai to become the first player to reach the semi-finals at the tournament's inaugural edition.
Williams, the top seed and seven-time Grand Slam winner, was stunned in the first set by 75th-ranked wildcard Zheng before she hit back to win 4-6, 6-1, 6-1 in Zhuhai, southern China.
"You could see that she played amazing and she really is a future champion," Williams said, according to the WTA website.
"First set, wow, she played so well until the last point. She definitely deserved to get the wildcard into this tournament - she has a lot of talent and there are definitely great things for her in the future."
In Group C, Czech third seed Karolina Pliskova beat Italy's Sara Errani 6-0, 6-3.