Fritz’s third-set mini-crisis was closely followed by the latest failure of the electronic umpire. Swedish umpire Louise Azemar-Engzell called 'stop' in the opening game of the fourth set on Court One when 'fault' was incorrectly called after a Fritz forehand landed well inside the baseline.

Taylor Fritz recovered from a mid-match lull during which he was treated by a trainer for a foot problem and reached the Wimbledon semifinals for the first time with a 6-3, 6-4, 1-6, 7-6 (4) victory over Karen Khachanov on Tuesday.

The 27-year-old beat the Russian 6-3, 6-4, 1-6, 7-6 (7-4) to reach the last four and keep his quest alive to become the first American man to win tennis' oldest major tournament in 25 years — Pete Sampras last lifting the SW19 trophy.