Wimbledon champion and world number one Novak Djokovic has withdrawn from next month's US Open hardcourt tuneup event in Montreal.

He says, he needs more rest after capturing his 16th Grand Slam singles crown. The 32-year-old Serbian, who outlasted Roger Federer in an epic All-England Club final earlier this month, was joined by Argentina's 12th-ranked Juan Martin Del Potro in pulling out of the ATP Masters Canada tournament. 

Del Potro was injured last month at Queen's and underwent right knee patella surgery and is undergoing rehabilitation for the setback. Djokovic's withdrawal means Spanish star Rafael Nadal, an 18-time Grand Slam singles champion, will be the top seed in Montreal when main draw begins on the 5th of next month.