David Goffin of Belgium advanced to the Japan Open quarterfinals after squeezing by Canada's Denis Shapovalov 7-6(7/5), 7-6(7/2) Thursday.
Both men kept all of their service games -- with Shapovalov nailing 10 aces against third-seed Goffin's four -- in the close match that lasted nearly two hours.
Goffin, winner here in 2017, used his footwork to survive two break points while the big-serving Canadian kept up the pressure.
Goffin will now face Chung Hyeon of South Korea, who pulled an upset victory against sixth-seed Marin Cilic 6-4, 3-6, 6-1.
"It was tough. We were both really solid on our service games," Goffin said of his match.
"But he (Shapovalov) was serving so well. A lefty, serving everywhere. Great second serves as well. So it was tough to break him today. So I had to fight."