July 15 was a big day in world sport. The FIFA World Cup final has historically always been a monumental event. But as France was celebrating their triumph long into the Russian night, back at the All England Club in London, a Serbian exhaled sharply, posing for the validation of his staggering comeback amid generous applause and shouts of "Daddy! Daddy!" from his 3-year-old boy, Stefan.

Novak Djokovic had won at Wimbledon only a month after he had thought he would never play on grass.

After 25 months of tribulation where he became a barely recognizable husk of himself, Djokovic was back, ostensibly a much more arrested version of himself. There were no grunts, no bellowing, no chest pounding and no tearing open his shirt. There was only a relief as Djokovic crouched down with his racquet under the overwhelming weight of emotions. Hardship seemed to have taught even an elite athlete such as Djokovic the value of restraint.

Standing three months since his fourth Wimbledon triumph, Djokovic is a 14-time Grand Slam winner having annexed his third US Open title in September and has now won the Shanghai Masters for a record-breaking fourth time.

Shanghai Masters
Novak Djokovic wins his fourth Shanghai Masters title on Sunday.WANG ZHAO/AFP/Getty Images

This year has been quite remarkable for Djokovic who also won the Cincinnati Masters in between his two grand slam triumphs. Having fallen as low as 22nd in the world only in May, Djokovic will leapfrog Federer into the second spot when the latest rankings are released on Monday and is currently enjoying an 18-match winning streak.

This comeback journey of Novak Djokovic did not come without its downs either. Even as recent as the first week of June, it seemed uncertain as to whether Djokovic would ever win a grand slam again.

He had lost to Italian journeyman, Marco Cecchinato in the quarter-finals of the French Open – at a juncture that fell very much on his comeback trail. Cecchinato was ranked 72 in the world and had not won a single grand slam match before the Roland Garros.

The Serb had been clearly rocked and in almost a daze, addressed the media post game, saying, "I don't know. I don't know if I'm going to play on grass. I don't know. I don't know what I'm going to do." Rubbing his face in disbelief, he went on to add, "How do I regroup? I don't know. I'm just not thinking about tennis at the moment."

The turnaround from there was not as much about his tennis as was about him recovering psychologically. Reuniting with his long-time coach, Marian Vajda had a decisive impact in Djokovic's comeback. Vajda, who played a massive role in reintroducing the joy of tennis to Djokovic, recalled in an interview to Dennik Sport that Djokovic was in self-doubt.

He said, "He called me from the Dominican Republic. We talked for around an hour. I caught him full of doubt." Vajda, thus, uncluttered his mind and took him back to his basics focussing on Djokovic's strengths – service, return, footwork, the baseline game and most of all, mental strength.

Novak Djokovic
Djokovic will move to the second spot behind Nadal, overtaking Federer on ATP men's singles rankings.Matthew Stockman/Getty Images

Although the Wimbledon victory was the confirmation of his successful comeback, the clincher had come to a match earlier when Djokovic battled Nadal for 5 hours and 15 minutes – in one of the most dazzling semi-finals the championship had ever seen – and eventually outlasted the Spaniard 10-8 in the fifth set.

Such was the effort that even Rafael Nadal, the man who always has the yard of endurance more than his opponent, conceded that he served his best shot and Djokovic returned better. Nadal was quoted post-match, "I have not much more inside me. I give my best, and that's it. I hit great shots. I played aggressive. [But] When you play with that intensity, with that level of risk, that level of passion, sometimes you go over, no?"

Competing in the Shanghai Masters this week, Djokovic cantered to victory without dropping a single set beating Cecchinato to love in the second set of his straight sets victory in the round of 16. In the final earlier today, the Serb cruised past Croatian, Borna Coric, 6-3 6-4. 

As Djokovic completes the circumference of greatness to wilderness and back to greatness – a story that has been of grit, self-belief and mental fortitude, it is almost certain that world tennis has rediscovered one of its most charismatic stars.