Friday 22 August 2014 07:32, UK
John Isner pulled out of the Winston-Salem Open ahead of his quarter-final against Lukas Rosol due to a sprained ankle.
Isner, the world no 15, sustained the injury to his left ankle on Wednesday evening during his third-round victory over Mikhail Kukushkin.
And, with the US Open starting on August 25, the 6ft 10in American opted not to risk aggravating the problem and instead withdrew a few hours before he was due to meet Rosol.
"There's not much motion in my ankle right now so that's what ultimately led me to this decision," Isner said.
"It's one of the toughest decisions I've ever had to make, as not playing last year was devastating and it's at the point where I can't risk further injury with the US Open around the corner. It's extremely disappointing.
"I'm playing well I don't feel like I'm short on matches as far as time on the court. Okay I'm not going to have as much time as I normally would but I'm going to do everything I can to get it as fit as possible."
Czech Rosol advanced to a semi-final against ninth seed Yen-Hsun Lu of Taiwan, who saw off Italy's Andreas Seppi 6-4 6-4 in the last eight.
Jerzy Janowicz had no problems in his quarter-final as he defeated David Goffin 6-4 6-2 while local favourite Sam Querrey recovered from a set down to win the other last-eight tie.
The big server lost the opener on a tie-break but responded well for a 6-7 (7/3) 6-2 6-4 success.
