Alex de Minaur advanced to the quarterfinals of the Erste Bank Open when Flavio Cobolli retired because of a shoulder injury with the Australian leading 7-6 (2), 3-1 on Thursday. The second-seeded De Minaur trails Andrey Rublev for the eighth and last spot for the ATP Finals next month in Turin. The Australian will face 19-year-old Jakub Mensik for a spot in the semifinals.