Chris Evert has backed her long-time rival and friend Martina Navratilova to win her latest cancer battle.

American tennis great Evert, who completed her own course of chemotherapy treatment in May after being diagnosed with ovarian cancer, said Navratilova's "strength and resilience" would stand her in good stead.

Navratilova has been diagnosed with throat and breast cancer, she announced on Monday. The Czech-American successfully underwent treatment for breast cancer in 2010 and has said the condition is "serious but still fixable" this time.

Evert's battles with Navratilova in the 1970s and 1980s provided one of the all-time great tennis rivalries.

Both women ended their careers with 18 grand slam singles titles, with Navratilova triumphing a record nine times at Wimbledon. Only Steffi Graf (22) and Serena Williams (23) have won more singles majors among women in the Open Era.

Evert posted on Twitter: "Thinking of @Martina today and supporting her journey, like she did mine, with love and prayers. This is a woman who takes on challenges with strength and resilience…You got this, Martina."

Former US Open champion Tracy Austin sent "prayers and hugs", adding: "Don’t know too many stronger, I know you got this my friend."

Navratilova's long-time former doubles partner Pam Shriver added: "@Martina knows how to put together a winning team. While the news today is difficult, Martina understands how to compete, and take care of herself.

"Her loving family and many friends are ready to support her journey one day at a time. You have this partner!"

Ons Jabeur, who was runner-up at Wimbledon and the US Open last season, said she was "sending my love and my support".