Novak Djokovic puts his remarkable longevity at the top down to hours of stretching before he even steps on court to practise.

While fellow 36-year-old Andy Murray was left to contemplate his future after crashing out in the second round to Stefanos Tsitsipas, Djokovic is bidding for a 32nd victory in a row on Wimbledon grass on Sunday, against 17th seed Hubert Hurkacz.

Still pencil thin and rarely injured, Djokovic is a freak of nature in defying the usual ageing process.

But his formula is less magic and more hard sacrifices. The Serbian's love of yoga and Tai chi extends to putting separators between his toes to aid flexibility.

He famously restricts his liquid intake to water and has written a book espousing the benefits of a gluten-free diet.

'I do feel great,' he said after reaching the fourth round without dropping a set. 

'I have an optimal body weight right now and there are also other important aspects to being dynamic, powerful and flexible.

'Tennis is a sport that is quite complex. It requires a player to have great balance between all physical traits.

'We all have different body types. I worked a lot on my flexibility from a young age as I was taught it would give me longevity. I focus a lot on prevention [of injuries]. 

'Before I get on the practice court, there's a lot of work that goes into it, a few hours of work before I actually get to training.

'It helps me. It helps extend my career and compete at the highest level. It helps me prevent injuries, God forbid, or anything like that.

'You see other players at this age, it's kind of expected to have a major injury because of the wear and tear of the body. 

'Luckily for me, I've had only one significant one, the elbow surgery that kept me off the circuit for almost a year.

'Other than that, there was some muscle tears but generally I've kept healthy considering the intensity of my career and the amount of matches I've played in the last 20 years.'

Djokovic is bidding for fifth Wimbledon title in a row and eighth altogether, equalling Roger Federer's record. 

Already the winner of more singles Grand Slams than any other male tennis player in history, he would also equal Margaret Court's best mark of 24 if he is successful in a week's time.

His immediate priority is to deal with the big-serving Hurkacz, who beat Federer in 2021 to end his legendary Wimbledon career.

Djokovic knows he will have to improve despite having sailed through the first three rounds, though he will be mindful that his last win against Stan Wawrinka was not completed until 10.46pm on Friday night.

'He [Hurkacz] covers the court very well. He has very long arms and, when he comes to the net, he closes it very well,' said the second seed.

'He plays a lot of doubles as well and has good success. For a tall guy, he defends well, even slides. Just overall a very complete player, I don't see too many holes in his game really. 

'It is definitely going to be the toughest challenge of the tournament so far for me but I can go up one or two gears from my last match.'