ATP rankings update: Novak Djokovic begins 360th week as World No. 1 but Daniil Medvedev is closing in

Novak Djokovic began his record-breaking 360th week as World No. 1 in the ATP rankings published on Monday. But the Serb's reign atop the world rankings could come under threat next week from his closest rival Daniil Medvedev.

Djokovic has not played a tournament so far this year. He was deported from Australia, causing him to miss the first Grand Slam of the season. The Serb will compete in the Dubai Tennis Championships next week while Australian Open finalist Medvedev will play in Acapulco.

Djokovic needs to fare better in Dubai than Medvedev does in Acapulco in order to retain the top spot. If he doesn't, the Russian will become the 27th man to top the ATP rankings list.

The duo are followed by Alexander Zverev (No. 3), Rotterdam finalist Stefanos Tsitsipas (No. 4), Australian Open champion Rafael Nadal (No. 5), Matteo Berrettini (No. 6) and Andrey Rublev (No. 7).

Argentina Open champion Casper Ruud, who won his seventh singles title on Sunday, remains at No. 8 while Felix Auger-Aliassime's first ATP singles title in Rotterdam sees him consolidate his position at No. 9. Jannik Sinner, who is rumored to be splitting from long-time coach Riccardo Piatti, rounded out the top 10.

Taylor Fritz, Reilly Opelka lead gains for the American men in ATP rankings

Taylor Fritz is now the highest-ranked American male player on the ATP list

Outside the top 10, American men enjoyed a good week on the ATP rankings list. Taylor Fritz jumped two positions to a career-high No. 17 while Reilly Opelka, who won his third career singles title in Dallas on Sunday, moved up three spots to No. 20.

Dallas semifinalist John Isner also climbed three rungs to No. 23 while Jenson Brooksby, who finished runner-up in Dallas, moved up nine spots to No. 45.

20-time Grand Slam winner Roger Federer, still missing in action since Wimbledon 2021, stayed put at No. 30 while another former World No. 1 Andy Murray climbed eight spots to No. 87 in the rankings.

Meanwhile, 20-year-old Jiri Lehecka, who reached the semifinals in Rotterdam as a qualifier on his ATP-level debut, jumped up 42 spots to No. 95.