"Thank you for all the support and messages," Dimitrov wrote. "Definitely not the way I wanted to leave North Carolina, I was really looking forward to a great week here."

He didn't feel well yesterday and it really hit him in the second set. "But I'm recovering well and will be fit for the US Open."

The top seeded Dimitrov had led 6: 0, 2: 4 against Dominic Thiem in the round of 16 when he had to give up after consulting the physio and the tournament doctor.