Second seed Venus Williams has been forced out of the Auckland Classic tennis tournament due to injury.
Williams beat New Zealander Jade Lewis in her first-round match this afternoon but then told officials that she could not continue in the tournament because of an arm injury.
Tournament director Karl Budge made the announcement this afternoon.
"She felt pain throughout her match against Jade, and wasn't able to serve as she'd ordinarily like to, and with the level we've come to expect from Venus, and unfortunately that's taken her away from the tournament this year.
"I'm pretty close with Venus. She's gutted and so am I, but she's got to do what's right for her, and if she can't perform at 100 percent at this level - you need to make sure you're making the right decisions."
In a short statement, Williams said: "I love this tournament and really sad that I have to withdraw, but I'm really happy to have had the opportunity to be here again this year."
It was her fourth appearance in Auckland, having won in 2015. She said she would stay in the city to follow the progress of her sister, Serena, who was the top-ranked player at the tournament.
It was unclear if she would be fit to play the Australian Open later this month.
Her absence hands Japanese teenager Naomi Osaka a free pass to Thursday's quarter-finals.
'I loved her intensity'
Williams needed a tie-break to take the first set over the 18-year-old Aucklander, before winning the second 6-2.
"I loved her intensity," she said. "She wanted to win and she expected a lot from herself."
"Those are all the things you want to see from a young person. I think she could do a lot in this game. She loves it and she wants more and I was happy to see that."