Ana Ivanovic has revealed a conversation she had with Rafael Nadal which arguably makes the unrivalled longevity of Novak Djokovic even more impressive. 

The former French Open champion recalled how Nadal told her in 2008 that he did not know “how long I will last”, while describing the fact Djokovic remains so healthy as “fascinating.”

Djokovic saw off world No 4 Jannik Sinner 6-3, 6-3 in the final of the 2023 ATP Finals in Turin on Sunday to claim a record seventh title at the year-end championships.

Despite turning 36 in May, Djokovic has had one of the finest seasons of his glittering career in 2023, having won seven tournaments, including six ‘big titles’ (Grand Slams, ATP Finals and Masters 1000).

The world No 1, who is 55-6 (90.2%) this season, secured three of the four Grand Slam tournaments this year, while he has won four of the last six Majors held.

The 24-time Grand Slam champion has now won 12 Majors in his 30s and has an incredible 12-3 record in Grand Slam finals since turning 30.

Only Ken Rosewall and Roger Federer have won a Grand Slam title at an older age than Djokovic managed at this year’s US Open, where he downed Daniil Medvedev in the final.

Speaking on the Alesto podcast, Ivanovic shared an anecdote about Djokovic’s great rival Nadal telling her he was unsure how long he would be able to continue playing 15 years ago.

“I remember Rafa telling me in 2008, ‘I don’t know how long I will last’, and here is Novak, he is fighting. The fact that Novak is so strong and healthy is really fascinating to me, kudos to him,” said the Serbian.

“Definitely, we all mature and age brings its own experiences. He has definitely changed. I think we are all constantly changing. Honestly, we didn’t think it (Djokovic’s success) would last that long.

“What’s really fascinating to me is how he manages to keep his body in good shape and healthy. It’s a hard sport, it has a big impact on the body, we can see it from Roger [Federer] and Rafa.”

Ivanovic, a former world No 1, retired in 2016 after winning 16 WTA titles. The 36-year-old won her only Major in the same year her fellow Serbian Djokovic won his first in 2008, while she and Nadal both triumphed at Roland Garros that year.

Djokovic will finish his 2023 campaign at the Davis Cup Final 8 knockout stage in Malaga, which will run from November 21-26 this week. Serbia will face Great Britain in the quarter-finals on November 23.

The 36-year-old is looking to help win a second Davis Cup title for Serbia, having led his nation to their only triumph in the history of the team competition in 2010.