NOVAK DJOKOVIC has revealed the one area of his game he must improve before the US Open.
Djokovic created history last Sunday when he overcame Roger Federer in the Cincinnati Open final to become the first player to complete a clean sweep of all nine Masters 1000 series titles.
The Serbian – who is seeded third for the US Open – has enjoyed an incredible transformation this season after missing the last six months of 2017 with an elbow injury.
Should he triumph at Flushing Meadows, Djokovic will lift his second Grand Slam title of the campaign and his third in New York.
But the 31-year-old – who is one of the in-form players going into the final Major of 2018 – admits he is still looking to make adjustments to his serve.
“It’s still a work in progress with the serve, to be honest,” Djokovic said.
“I’m aware that I can’t serve as the guys who are 6ft 10in obviously can.
“I’m not looking for that speed – I’m looking more for precision and accuracy.”
Despite his climb up the rankings, Djokovic has warned his rivals his best is yet to come.
He said: “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.”
The US Open gets underway on Monday.