Djokovic, who won the Australian Open for a ninth time in February, is expected to set a new record when the next set of ATP rankings are released March 9. The Serbian's current reign atop the rankings started Feb. 3, 2020. He has ranked No. 1 through five separate stints.
His longest streak as the top player lasted 122 consecutive weeks from July 7, 2014, through Nov. 6, 2016. Federer still holds the record for the longest consecutive run as the No. 1 player. His record streak lasted 237 consecutive weeks.
Djokovic, 33, made his professional debut in 2003. He first broke into the ATP's Top 100 in 2005 and climbed into the Top 10 in 2007.
He went on to win the 2008 Australian Open for his first career Grand Slam title. The 18-time Grand Slam champion also has five Wimbledon singles titles, three U.S. Open titles and won the 2016 French Open.
Djokovic needs two more Grand Slam titles to tie Federer and Rafael Nadal for the men's record.
He was 24 years old when he first achieved the No. 1 world ranking. Djokovic owns a 387-53 record when ranked No. 1. He is 37-5 over his current tenure as the top men's player.
Nadal, Daniil Medvedev, Dominic Thiem and Federer also rank inside the Top 5 in the latest ATP rankings. Stefanos Tsitsipas, Alexander Zverev, Andrey Rublev, Diego Schwartzman and Matteo Berrettini rank inside the Top 10.
John Isner (No. 25) is the highest-ranked American player.
Australian Alexei Popyrin had the biggest jump in the rankings. He moved from No. 114 to No. 82. Popyrin made it to the round of 64 at the Australian Open and won the 2021 Singapore Tennis Open title Sunday in Singapore.