Australian third-seeded Australian Alex de Minaur saved six of eight break points to beat qualifier Aslan Karatsev of Russia 6-4, 7-6(5) in one hour and 51 minutes on Wednesday for a place in the Sofia Open quarter-finals.
The 21-year-old, who reached the European Open final in Antwerp (lost to Humbert) last month, recovered from 3-5 down in the second set and saved two set points at 4-5, 15/40. He will next play Italian Jannik Sinner or lucky loser Marc-Andrea Huesler of Switzerland.
Fifth-seeded Frenchman Adrian Mannarino recorded his 13th match win of the season to overcome Egor Gerasimov of Belarus 6-4, 7-6(6) in one hour and 47 minutes and now challenge Moldovan Radu Albot, who overcame top-seeded Canadian Denis Shapovalov in the second round on Tuesday.
Sixth-seeded Australian John Millman dug deep to beat Gilles Simon of France 7-5, 6-7(3), 6-2 in three hours and 15 minutes. Millman recovered from 2-4 down in the first set and could not convert two match points at 6-5 in in the second set. The 31-year-old captured his first ATP Tour title at the Astana Open in Nur-Sultan (defeated Mannarino) on 1 November. He now faces Canada’s Vasek Pospisil.