Djokovic spent the last six months of 2017 sidelined with an elbow injury which required surgery.
The Serbian struggled to return to top form and it was not until the grass-court season where he really began to rediscover some of his best tennis.
Djokovic beat world No 1 Rafael Nadal in the Wimbledon semi-finals in a blockbuster clash which lasted over five hours.
He then slayed Federer in the Cincinnati Masters final last week – proving to the world that he is back for good.
But Djokovic thinks there is still more in the tank and he has warned his rivals that he will get even better when the US Open starts next week.
“I want to say a great thanks to my team for sticking with me in the tough times,” Djokovic said.
“I was injured and I was struggling to get back on the court and in the right form.
“I am grateful for where I am at the moment and I couldn’t be in a better place before the last Grand Slam of the year.
“I do feel like I am playing close to my best, I still feel I can play better.
“In the finals against Roger it was definitely the best match of the tournament.
“I can have the consistently high level and hopefully a good tournament.”
Djokovic wrote his name in the history books with his latest success in Ohio.
The former world No 1 became the first ever player to win all four Grand Slams and all nine Masters 1000 events.
And Djokovic was delighted with his incredible achievement.
“I played five finals (here) before, and most of those finals I lost to this great man, Roger … thank you for letting me win here once in Cincinnati,” Djokovic said.
“This is a dream come true.
“I finally won Cincinnati after six finals, some against the greatest ever, Roger.”