Stefanos Tsitsipas needed three sets to defeat former world number four Kei Nishikori 6-3, 3-6, 6-1 on Monday night.
The Greek player got off to a rapid start with a 3-0 lead before going on to wrap up the opening set after losing only four points on his own serve.
Nishikori fought back in the second, taking a 3-0 lead before holding his nerve to see out a tense leveller.
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But Tsitsipas broke the Nishikori serve in a 10 minute opening service game in the third and momentum swung the 22-year-old's way. He sealed the tie in one hour and 56 minutes.
The Greek will meet Lorenzo Sonego in the next round, who defeated Daniel Elahi Galan 7-6(6), 6-3.
Russian fourth seed Andrey Rublev has set up an exciting clash against former world number three Marin Cilic in the Round of 16 after he eased past Marton Fucsovics 6-2, 6-1 while the Croat swept away highly-promising Italian Lorenzo Musetti 6-3, 6-4.
It was a day of mixed fortunes for the Canadian representatives. Denis Shapovalov lost 6-4, 7-6(6) to Hubert Hurkacz on the same day compatriot Milos Raonic defeated Ugo Humbert 6-4, 7-5.
Diego Schwartzman comfortably saw off Adrian Mannarino 6-1, 6-4 in one hour and 17 minutes and Australian Open semi-finalist Aslan Karatsev fell 6-3, 6-0 to world number 87 Sebastian Korda in 69 minutes.
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