The 22-year-old Draper earlier this month became the first British man to reach the US Open semi-finals since Andy Murray won the title 12 years ago.

He was looking to build on his success in Tokyo but he needed medical treatment on his upper body late in a first set that Humbert won 7-5.

The Frenchman was leading 2-1 in the second when Draper signalled that he could not continue.

"I feel sorry for him because he was not 100 percent but at least we played an amazing first set with a great level, great intensity," said Humbert.

"I'm just happy to be in the semis."

Draper had not dropped serve in two matches heading into the quarter-finals in Tokyo but Humbert broke him three times in a hard-fought first set.

Humbert, who is ranked 19th in the world and has won two titles on the ATP tour this year, will face the Czech Republic's Tomas Machac in the semi-finals.

Machac beat American qualifier Alex Michelsen 7-6 (7/2), 6-3 in the day's first quarter-final.

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