Martina Navratilova has revealed what impresses her most about fellow tennis legend Serena Williams.

Williams, 40, currently boasts 23 Grand Slam titles, trailing only Margaret Court’s 24 on the all-time singles list.

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Navratilova – who won a combined 59 Grand Slam titles (18 singles, 31 doubles and 10 mixed doubles) – says what Williams achieved after turning 30 stands out.

“What’s most impressive for me is how she [has] won so many majors after she turned 30,” Navratilova said on the ‘The GOAT: Serena’ podcast.

“Because, it gets harder when you get older. At the same time she was a relatively young 30 in that she didn’t play that many matches.”

Williams won 10 of her 23 singles majors after the age of 30. Navratilova, in comparison, made 10 Grand Slam finals in her 30s, winning three (1987 Wimbledon US Open and 1990 Wimbledon).

Williams played in 16 Grand Slam finals since turning 30, winning 10.

She has however lost her last four major finals, with her last triumph coming at the 2017 Australian Open when she beat sister Venus in the final.

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Picture: Serena Williams – USTA/Twitter