Spanish teen Carlos Alcaraz, the youngest US Open quarter-finalist in 58 years, was forced to retire from his match Tuesday at the US Open with a right adductor injury.

Canada's Felix Auger-Aliassime led 6-3, 3-1 when 18-year-old Alcaraz retired from the match, sending his 21-year-old rival into his first Slam semi-final aganst Russian second seed Daniil Medvedev.