Novak Djokovic's former coach Boris Becker believes that the main challenge that faces the Serb after such a major injury layoff is mental where he has to learn to do the dirty work and keep practising to reach his best, without always reaping the rewards.

The time taken by a professional to return to his best is usually equivalent to the time he was off, but Becker is hopeful that it will not be the same for Djokovic as it would mean the end of the year for his return. The German had coached Djokovic to six Grand Slam titles between 2014 and 2016 but a loss in form coupled with injury issues saw the 30-year-old lose his grip at the top.

The 12-time grand slam singles champion has not played since losing to Hyeon Chung in the Australian Open fourth round, after which he underwent a "small medical intervention". The Serbian had already missed the better part of 2017 with an elbow injury and is making good strides to return to his best after suffering a setback in Melbourne.

However, Becker is optimistic of Djokovic's chances to make a comeback, having seen the likes of Rafael Nadal and Roger Federer create history after returning from injury in 2017. Both players dominated the Slams in 2017 — winning all four events — sharing two apiece while the Swiss star defended his Australian Open in January, claiming a 20th major.

"Mentally is going to be the biggest challenge," said Becker, as quoted by AFP. "How much you accept to do the dirty work like Monday morning practice, the first and second round of tournaments you are expected to win and it is hot and windy conditions.

"Usually they say the amount of time you have been away takes you the same amount to come back to your previous level and I hope that is not the case for Djokovic because that would mean the end of the year."

"It would be a lot to expect him (Djokovic) coming back and winning his first tournament at a Grand Slam, Rafa and Federer have set examples of coming back but they are not normal. Usually it takes time."