Novak Djokovic set a new landmark of 311 weeks as World No. 1 on Monday, one week longer than Roger Federer whose tally of a record 20 Grand Slam titles the Serb is now “devoted” to breaking. 

Djokovic, 33, won his 18th major at the Australian Open in February. With Federer turning 40 in August, the Serb has time on his side. He is a year younger than Rafael Nadal who also has 20 majors. “The two main goals in tennis are probably the number of Grand Slams won and the number of weeks spent at number one,” Djokovic told Serbian broadcaster RTS.