Denis Shapovalov secured a straight-sets win over Jeremy Chardy to set up a semi-final showdown with qualifier Lloyd Harris at the Dubai Tennis Championships.
The third seed struck 26 winners en route to a 7-5 6-4 triumph on Thursday, but it was his serve that pleased him most.
Shapovalov, ranked 12th in the world, sent down 10 aces as Frenchman Chardy, winner over Australian No.1 Alex de Minaur earlier in the tournament, was deprived of any break-point openings.
“I’ve focused on my serve a lot in the past couple of weeks,” the Canadian said.
“I have worked on placing it and tried out different types of serves to have more variation. I hope I can continue that.
“I’ve also worked on my footwork and positioning during rallies. I am feeling the ball well on both sides. If I am moving well, everything goes into place.”
Harris provided a big surprise, beating the former world No.4 Kei Nishikori 6-1 3-6 6-3.
Second seed Andrey Rublev defeated Marton Fucsovics 7-5 6-2 and will now face fellow Russian Aslan Karatsev, who has not stopped making progress since his extraordinary run through to the Australian Open semi-finals.
Wildcard Karatsev beat rising teenager Jannik Sinner, coming from a set down in a 6-7 (5-7) 6-3 6-2 win.