British No.1 Jack Draper retired due to injury in his Japan Open quarterfinal against France's Ugo Humbert on Sunday.
The 22-year-old, who made a dream run to the U.S Open semfinal this summer, had lost the first set 7-5 and was 2-1 down in the second set before going off.
Draper had secured his place in the quarterfinal after a dominant straight-sets win over No. 2 seed Hubert Hurkacz on Friday. It was his third win against a top-10 ranked opponent this season.
