But he has never reached a Grand Slam quarter-final, although the longer best-of-five format has worked twice in his favour now at Roland Garros. "I'll get myself ready", Zverev said, smiling.
Zverev was forced to save match point on serve at 4-5 down but survived and eventually secured his first third-round win at the French Open.
The 21-year-old German edged out Russia's Karen Khachanov 4-6 7-6 (4) 2-6 6-3 6-3 and has progressed to his first Grand Slam quarter-final where he will face Austrian Dominic Thiem. "I'm very happy about being in the quarterfinals here, going the hard way, going the long distance ... showing everybody that I can play for as long as I need to".
Zverev's class and persistence shone through in the final set as he took an early break and converted match point on Khachanov's serve. "This definitely paid off, the hours in the gym every day ..."
The second seed, a quarter-finalist in Paris past year, will face Daria Kasatkina for a place in the last eight after the Russian beat Maria Sakkari 6-1, 1-6, 6-3.
Could this be the turning point for Zverev at Grand Slams? Khachanov punished him and broke for 5-5.
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The second-set tiebreaker was scrappy, Zverev clinching it with an ace to level the match. At the start of the fifth set, he had a medical timeout for treatment for an apparent blister on his left foot.
Three-time champion Williams is playing her first Grand Slam tournament since taking time off last year due to pregnancy, while Sharapova is at Roland Garros for the first time in three years after serving a doping ban in 2016 and being refused a wildcard 12 months ago.
Djokovic claimed a hard-fought 6-4, 6-7 (6/8), 7-6 (7/4), 6-2 victory over a grieving Roberto Bautista Agut.
Dabrowski will also return to women's doubles action Monday when she teams with China's Yifan Xu for a third-round match against the Japanese duo of Makoto Ninomiya and Eri Hozumi.
In the women´s draw, Australian Open champion Caroline Wozniacki eased past Frenchwoman Pauline Parmentier 6-0, 6-3.
Stephens, the 10th-seeded American, also reached the last eight in Paris for the first time, beating No. 25 Anett Kontaveit of Estonia 6-2, 6-0.