(CNN)Novak Djokovic has achieved another milestone in his illustrious tennis career, surpassing Steffi Graf to spend the most weeks at No. 1 in the world.
On Monday, Djokovic started his 378th week as the Association of Tennis Professionals (ATP) world No. 1, spending the most weeks in that spot since the ATP ranking system began in 1973.
A week ago, Djokovic matched the Women's Tennis Association (WTA) leader, Graf, who held the top spot for 377 weeks in her career.
"With your love and great strength that you have given me over the years, I've managed to achieve many fantastic achievements throughout my career," Djokovic said in a video message to fans, shared by the ATP.
"The most recent one breaking the record of 378 weeks on No. 1 rankings, surpassing one of the greatest, most legendary tennis players -- both men and women -- that ever played, Steffi Graf. So I'm flattered, obviously extremely, extremely proud and happy for this achievement."