Martina Navratilova, the retired tennis great who won 18 Grand Slam singles titles during her illustrious career, announced Monday recent tests have shown that she is cancer free.

The 66-year-old said she had a full day of testing at Sloan Kettering Cancer Center and the results have come back clean.

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Martina Navratilova gets the golden racket

Former Czech tennis player Martina Navratilova receives the golden racket during the Italian tennis internationals at the Foro Italico in Rome May 21, 2023. (Massimo Insabato/Archivio Massimo Insabato/Mondadori Portfolio via Getty Images)

"Thank you to all the doctors, nurses, proton and radiation magicians etc- what a relief," she wrote on Twitter.

Navratilova announced in January she was diagnosed with throat and breast cancer and that she would begin treatment in a month. She had been diagnosed with a noninvasive form of breast cancer in 2010 and had a lumpectomy.

"This double whammy is serious but still fixable," she told The Times earlier this year. "I’m hoping for a favorable outcome. It’s going to stink for a while but I’ll fight with all I have got."

Martina Navratilova in Rome

Former Czech tennis player Martina Navratilova receives flowers during the Italian tennis internationals at the Foro Italico in Rome May 21, 2023. (Massimo Insabato/Archivio Massimo Insabato/Mondadori Portfolio via Getty Images)

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She noticed an enlarged lymph node in her neck back in November and a biopsy revealed the early stage throat cancer. She felt well enough to return to her TV work with the Tennis Channel by the Miami Open in March.

Navratilova is considered one of the greatest tennis players of all time – up there on the Mount Rushmore list with Serena Williams, Chris Evert, Billie Jean King and Margaret Court. She was ranked No. 1 in the world for 332 weeks and won 59 major titles across singles, doubles and mixed doubles competitions.

Martina Navratilova shields her face

Martina Navratilova in London in 2004. (Bongarts/Bongarts/Getty Images)

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Notably, she won nine Wimbledon titles.

The Associated Press contributed to this report.