Jack Draper was on Sunday forced to retire from his Japan Open quarter-final due to injury.
The British no1 was trailing 5-4 to France's Ugo Humbert in the opening set before requiring on-court treatment.
Draper, playing his first ATP Tour tournament since his run to the semi-finals of the US Open earlier this month, initially continued before pulling out while trailing 7-5 2-1.
The 22-year-old had his stomach muscles massaged during the medical timeout but continued to look in discomfort.
World no19 Humbert, who is ranked a place higher than Draper, will take on Czech player Tomas Machac for a place in the final.
Following the coin toss and warm-up, the start of the match was briefly delayed by rain, with the players leaving the court as the roof was closed.
Draper and Humbert were each broken twice in the opening nine games before the former called for the physios.
The Briton, who lay at the side of the court for treatment, then successfully served to stay in the first set.
But he was broken in his next service game as fellow left-hander Humbert seized the initiative with a stunning cross-court forehand.
Draper managed a further three games before trudging from court after calling time on the contest.
