Zverev will face Thursday for a place in the quarterfinals Andrey Rublev (33) who eliminated John Millman (58).
The first loose set took the two men to tiebreak in about forty minutes. But the decisive game was very tense and went on forever.
It is finally Zverev who, thanks to his service and on a long ball of Chardy, won this first round.
In the second, the French led 5-3 and then served for the set at 5-4, but only one breaker was enough for the German to tie at 5-5.
The decisive game was much faster than the first and also turned in favor of the German. He knew, at this time of the game, to raise his level which had until then been far from the one displayed in the semifinals of Beijing last week, where he had given in to Tsitsipas.
His relaxation at the very end of the game was particularly marked by the loss of his racket on a forehand shot: his tool slipped his hands and flew into the audience, without injury or damage.