Daniil Medvedev made his mark on Monday, at the Nitto ATP finals in the opening round defeating 2018 champion Alexander Zverev, following his disappointing run last year on his debut.
The Russian is now tied at the top of the Tokyo Group alongside world number one Djokovic, who defeated Argentine debutant Diego Schwartzman in straight sets.
Medvedev will play the world number one on Wednesday, who is bidding to equal the six of tennis great Roger Federer.
