As far as the Serbian's record this year is concerned, he finished 55-7, as he won three Grand Slams this year (Australian Open, French Open and Wimbledon). Besides, he also won the Belgrade Open and Paris Masters. His current number one stint began in February last year. He will be eyeing the all-time record of legendary former tennis legend Steffi Graf of Germany, who had held on to the number one ranking for 377 weeks.