John Isner has edged out fellow American Jack Sock to reach the semi-finals of the Paris Masters.
Isner has endured an indifferent year on the ATP Tour and now finds himself at number 27 in the world rankings, but he is ending the year in positive fashion after a three-set victory over Sock.
The 31-year-old edged the opening set on a tie-break but Sock responded to that disappointment by breaking serve twice in the second.
However, his own delivery started to falter in the decider and Isner struck two times to secure a 7-6 4-6 6-4 triumph.
Isner will now face either Novak Djokovic or Marin Cilic in the last four on Saturday.
