John Isner has retired from his second-round match at Wimbledon against Adrian Mannarino with a left knee injury.
The 18th-seeded American had won his opening service game and Mannarino was 15-0 up on his serve when Isner called for a medical time out.
The trainer put wrapping around Isner's knee. He returned to play but was clearly hobbled and unable to run for the ball.
Mannarino won his service game to make it 1-1, then Isner served one point before deciding to stop.
The retirement came three years after Isner won the longest match in tennis history, beating Nicolas Mahut 70-68 in the fifth set in a Wimbledon match that lasted more than 11 hours over three days.
Isner was bidding on Wednesday to reach the third round at the All England Club for the first time.