"The level of fitness is higher on tour all the way around, and Novak has this willingness to go one shot deeper in the rally, to use his legs.
That is going to be important for him: Can he be healthy?
He's not like [Roger] Federer, who can attack at will. It demands a pretty high level of sophistication."Federer's choice to cut off his season in 2016 at the halftime mark because of lingering injuries looked like the ultimate sophisticated decision.
He came back better than ever in 2017, winning in Australia and then at Wimbledon for a previously unfathomable eighth crown there.
He was facing Tomas Berdych in the quarterfinals, and after losing the first set, Djokovic hit a sloppy forehand wide in the second, then walked toward the net, shaking his head in frustration. The US Open in late summer marked the first Grand Slam he had missed in more than 12 years, a streak of 51 majors played in a row snapped, dating back to the Australian Open in 2005.
Before Novak Djokovic could entertain the idea of returning to top form, the 12-time Grand Slam champion ended 2017 by withdrawing from an exhibition in Abu Dhabi.
It was a fitting end for a player who is coming off the most disastrous year of his storied career.
14 hopes has refreshed him mentally and physically.
He is an athlete who relies on his body perhaps more than any other in this sport."His game is certainly tied to his fitness," said former touring pro Leif Shiras.