World No 1 Novak Djokovic will head into the US Open with minimum preparation after pulling out of the Cincinnati Masters 1000 event.

The Serbian superstar is seeking to complete a calendar-year Grand Slam at the US Open after winning the year’s first three majors.

He is also not competing at this week’s Masters 1000 event in Canada and said on Monday he needed more time to recover after the Olympic Games in Tokyo, where he lost in the semi-finals to Germany’s Alexander Zverev and also to Spain’s Pablo Carreno Busta in the bronze medal match.

“I’m taking a bit longer to recover and recuperate after quite a taxing journey from Australian Open up to Tokyo,” Djokovic wrote on social media.

“Sadly, this means I won’t be ready to compete in Cincinnati this year so I’ll be turning my focus and attention to the US Open and spending some more time with family. Can’t wait to see you in New York soon!”

Djokovic will now head into the year’s final Grand Slam slightly underdone.

If he wins the US Open, he will become the first man since Rod Laver in 1969 to win all four Grand Slam titles in one year.