Madison Keys of the US hits a return against Greece's Maria Sakkari during their women's singles match on day five of the Australian Open tennis tournament in Melbourne on Jan 24, 2020. (PHOTO / AFP)

Madison Keys announced Thursday she tested positive for COVID-19, weeks ahead of the Australian Open.

The No 16-ranked woman in the world, Keys implied in her statement she would miss the Australian Open, which opens Feb 8. She was scheduled to fly to Australia and quarantine there for 14 days in advance of the season’s first Grand Slam tournament.

On the men’s side, former World No 1 Andy Murray also tested positive, and his appearance in the Australian Open is in doubt.

Keys, ranked five spots behind fellow American Serena Williams, has five career singles titles. Her best finish in the Australian Open came in 2015, when she lost in the semifinals to Williams

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“I’m very disappointed to not be able to play in the coming weeks after training hard in the off-season and knowing Tennis Australia and the tours did so much to make these events happen,” Keys, 25, said in a statement posted to Twitter.

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“I am self-isolating at home and will continue to follow all the necessary health precautions. I look forward to being back on tour next month.”

Keys, ranked five spots behind fellow American Serena Williams, has five career singles titles. Her best finish in the Australian Open came in 2015, when she lost in the semifinals to Williams.