Djokovic's Dad: Murray can be one of the greats, if he calms down. But why is Federer still playing?

Srdjan, who was speaking to the European edition of Newsweek magazine, says that “once he starts losing, his mind turns around and he looks lost”, adding that he needs to improve to ‘take more out of Novak’.

“If he learns to calm down,” he says in a rare interview, “he will have a far bigger career than he has by now.

"I would love for Murray to achieve his potential.”

He added: “Murray is a great, great talent – one of the biggest ever, and a big part of it is not being used because his mindset is not calm. He gets frustrated very easily.

"When he’s winning he has booming confidence but, once he starts losing, his mind turns around and he looks lost. He starts talking to his box, and this distracts his mind.

"They key for Murray will be to emulate Novak, Srdjan believes, and to say to himself, 'I need to make myself better in this and this'."

“When Federer and Nadal were the best two players in the world, they took much more out of Novak.

"For a couple of years Novak was giving his best and trying everything, changing his forehand, his serve, because he had a goal to beat Nadal and Federer.

"Now Murray has to do the same.

“He needs to put himself in the same position: to say, ‘OK, Novak, you are better at this and this. I need to make myself better in this and this in order to get there.’ They make each other better.”

Djokovic has beaten Murray 22 times in 31 matches, and most recently at the first Grand Slam of the season in Melbourne, and Srdjan has no doubt that his son will prove himself to be the greatest player to have lived.

“[Novak] will be the best tennis player in history,” he said. “I have been saying it since he entered tennis. Surely he will be one of the best sportsmen ever.

“All of it is because he was sent from God. As a family, we tried to make God’s wish come true. He can win another 10 Grand Slams.”

Srdjan moved on to describe his son and Murray as “amazing friends”, but had less than complimentary things to say about another of Novak’s big rivals, Roger Federer.

“[They are] amazing friends,” he said of Novak and Murray. “At the moment they cannot be good friends outside of tennis, because they are rivals.

“But, once they have finished their careers, they are going to be much better friends than they are today.”

As for Federer: “When Serbia played Switzerland in Geneva [in 2006], Novak was just 19 at the time. He had a deviation of his sinuses and couldn’t breathe. He had a problem with staying in long matches and long points.

“Federer tried in every possible way to disrespect him because of his breathing problem. He showed himself to be the best player in the world but not as a good person at that time. Nobody has ever treated Novak like this.

“I don’t understand why Federer is still playing tennis. Why does he still play? He’s already 34.”

Where do we start with these quotes? While Djokovic certainly appears to have the beating of Murray right now, it is not fair of Srdjan to say that the Brit needs to learn to calm down given all that he has already achieved in the sport and how much he has improved in this aspect since he first arrived on the ATP Tour. He is not alone in believing that his son could end up being “the best tennis player in history”, but he still has a way to go to surpass Federer as things stand.

Finally, his views on Federer appear to be bizarre at best. The Swiss is still playing because he enjoys what he is doing and believes he has more to offer and trophies to collect – given everything he has given tennis, he has a right to leave the game when he chooses to.