Coco Gauff has had to pull out of the Olympics after testing positive for Covid-19.
The 17-year-old confirmed on social media that she would not be able to represent the USA in the Tokyo games.
The world number 25 would have been among the biggest draws in an Olympics that has already been hit by high-profile withdrawals in both men's and women's tennis.
Roger Federer, Rafael Nadal, Stan Wawrinka, Serena Williams and Simona Halep have all previously withdrawn from the Tokyo games.
"I am so disappointed to share the news that I have tested positive for COVID and won't be able to play in the Olympic Games in Tokyo," Gauff posted on Twitter.
"It has always been a dream of mine to represent the USA at the Olympics, and I hope there will be many more chances for me to make this come true in the future.
"I want to wish TEAM USA best of luck and a safe games for every Olympian and the entire Olympic family."
