Zverev ready for 'best in world' at French Open
The German third seed will be well rested for the latter stages of the tournament after his last-16 opponent Tallon Griekspoor retired with an abdominal injury while trailing 6-4, 3-0.
Zverev, who lost to Carlos Alcaraz in last year's Roland Garros final, will face either Djokovic or Britain's Cameron Norrie in the last eight as he continues his latest bid for a maiden Grand Slam title.
"For me, Carlos is the favourite. I have said that before. Then I would say the next three in line are Jannik, myself, and Novak, right?