That is the opinion of Greg Rusedski.
Djokovic earned his second Grand Slam win of the year after Wimbledon and the 14th of his career with a 6-3, 7-6 (7-4), 6-3 win over Juan Martin del Potro in the final of the US Open.
The 31-year-old took his career total of major titles to 14, level with American icon Pete Sampras, to move three short of Rafael Nadal and six off of Roger Federer.
Djokovic was in imperious form to see off Del Potro – in his first Grand Slam final for nine years since winning this tournament in 2009 – and wore the Argentine down to climb to world No 3.
The Serbian’s back-to-back major successes hugely increase his chances of catching rivals Federer and Nadal having gone two years without a major win between the 2016 French Open and Wimbledon.
And former US Open finalist Rusedski believes that Djokovic has every chance of catching Federer and becoming the all-time leader in Grand Slam triumphs.
Rusedski told Amazon Prime: “Novak was by far the best player of this tournament.
“Del Potro found a way to get back into the match after being down 6-3, 3-1 and then he threw the kitchen sink at Djokovic – defensively he was quite incredible.
“The way the court was playing, it was slow, the roof was closed. Everything was going in his favour as it was with Wimbledon in the semi-finals against Rafael Nadal.
“If I look at what Djokovic has done in the last months, in Miami he was in the wilderness and nowhere near the player he once was, then he hired the team, got back his trainer, got back his physio and that is why he is enjoying this moment so much.
“Two Grand Slam titles this year – incredible feat. I think he’ll be No 1 in the world by the end of the year as well as the man to beat and don’t be surprised if he ties Federer’s record of 20 or gets even more the way he’s playing at the moment.
“If Del Potro would’ve found a way to win that second set, the crowd would’ve exploded and we would’ve had a match. That was the key of the match.
“All of a sudden there was one game that went 20 minutes, had he managed to break, serve out the second set – this thing could’ve gone four or five sets and at that stage anything could happen.
“But Djokovic showed us why he is going to be No 1 again. He’s won two majors so if you look at the majors this year, it was Federer in Australia, Rafa at the French and now Djokovic – Wimbledon was impressive and this one even more so.
“The expectation was, Djokovic was the man to beat at the start of these championships.
“The conditions being cooler helped. It’s about 15 degrees cooler than it was with the humidity and the heat and he was struggling but this is what the great champions do. They find a way to get through and he got better and better with every match.
“You never write off a great champion – whether it’s Federer, Nadal or Djokovic. I’m a little frightened for everybody last year, I think he’s going to win the Australian Open. He’s the heavy favourite to do so and he looks like he’s getting to that form where he once dominated men’s tennis.”