Australian Open champion Jannik Sinner reached the Rotterdam semi-finals on Friday when injury-plagued Milos Raonic was forced to retire at 1-1 in the second set of their last-eight clash. Top seed Sinner took the first set 7-6 (7/4) before the big-hitting 33-year-old Canadian called it quits after two more games. Sinner goes on to face Dutchman Tallon Griekspoor, who defeated Emil Ruusuvuori of Finland, 7-5, 7-6 (7/4) for a place in Sunday's final. "Obviously this is not the way you want to win the match," said Sinner.