Novak Djokovic, seeking to complete a calendar-year Grand Slam at the US Open, withdrew from the ATP Cincinnati Masters on Monday, saying he needed more recovery time after the Tokyo Olympics.

The top-ranked Serbian star, level for the all-time men’s record of 20 Grand Slam titles, could become the first man since Rod Laver in 1969 to win all four major titles in one year.

Djokovic, 34, lost at Tokyo to Alexander Zverev in a semi-final and Pablo Carreno Busta in the bronze medal match in what will be his last matches before the US Open after pulling out of the last major tuneup event.

“I am taking a bit longer to recover and recuperate after quite a taxing journey from Australia to Tokyo,” Djokovic posted on social media.

“Sadly, that means I won’t be ready to compete in Cincinnati this year so I’ll turn my focus and attention to US Open and spend some more time with family. See you in New York soon!”

Djokovic is a two-time winner of the Cincinnati event, including last year, when it was played in New York due to the Covid-19 pandemic.

The Cincinnati field still features five former champions, including Spain’s Rafael Nadal, 2019 winner Daniil Medvedev, Marin Cilic, Grigor Dimitrov and two-time winner Andy Murray of Britain.