Denis Shapovalov, Aslan Karatsev through to semi-finals of Dubai Duty Free Championships

Dubai: Denis Shapovalov put together another serving clinic to storm into the 12th semi-final of his career with a 7-5, 6-4 victory over French veteran Jeremy Chardy in Dubai on Thursday, while Aslan Karatsev ousted No 16 seed Jannik Sinner.The third-seeded Shapovalov has yet to drop a set this week in the Emirates, and has not been broken in all 28 service games he has played through three matches.The 21-year-old Canadian fired 26 winners and lost a mere six points on serve throughout the contest against Chardy.In what will be his third semi-final appearance since the tour restarted from its hiatus last August, Shapovalov will take on either Kei Nishikori or Lloyd Harris."I definitely focused on my serve a lot the last couple of weeks in practice, just putting a lot of time into it, placing it, trying different serves out and trying to have more variation," said the world No 12.Shapovalov and Chardy went neck and neck for the first 10 games before the explosive lefty finally got his hands on a break point, courtesy of a brilliant backhand return winner. The Canadian comfortably served out the opening set, at love, on the 46-minute mark.A crucial break in game nine gave Shapovalov the edge in the second set, and he wrapped up the win with his 10th ace of the match.Meanwhile, Karatsev backed up his surprise run to the Australian Open semi-finals last month by advancing to the last-four stage in Dubai with a hard-fought 6-7 (5/7), 6-3, 6-2 win over Italian teenager Sinner.The 27-year-old Karatsev, who started the year ranked 114 in the world before his breakthrough showing in Melbourne, came back from a set down for a second consecutive match in Dubai.The Russian wildcard unleashed 41 winners against 25 unforced errors during the two-hour 49-minute quarter-final and will next face second-seeded Andrey Rublev or Hungarian Marton Fucsovics."From the beginning, it was tough to get used to the rhythm, he's playing so fast, he's a really talented guy, he's a top player. It took me time to get used to the rhythm and then in the tiebreak I was a bit unlucky. The second set I started to feel better, more comfortable," said the 42nd-ranked Karatsev.