A line judge keeled over and fainted in Rafael Nadal's marathon five-set thriller against American Robert Kendrick at Wimbledon on Thursday.

"It was a weird start to my Centre Court. I hope the guy is all right," Kendrick said after the interruption to play.

"I thought he was maybe having a heart attack. I didn't know what was going on. I was sad to see that. I was just ready to serve and I heard a loud thump. Then I saw blood, he is holding his chest," Kendrick said.

Organisers said the linesman, whose name was not given, rested afterwards and had recovered. "We will see how he is tomorrow before deciding if he can line judge again," a spokeswoman said.