USA's Sam Querrey celebrates winning his match against Serbia's Novak Djokovic at the All-England Lawn Tennis & Croquet Club, Wimbledon, England, July 2, 2016. [Photo/Agencies]

Overpowered me

"Congratulations to Sam. He played a terrific match," Djokovic said shortly after walking on court. "He serves very well. I think that part of his game was brutal today.

"He just overpowered me."

Querrey was the first American to beat Djokovic in a Grand Slam since Andy Roddick in 2009 and he will take on Nicolas Mahut of France with a place in a first Grand Slam quarterfinal beckoning.

"It's incredible, especially to do it at Wimbledon, the biggest tournament in the world," said the world number 41 who had lost eight of nine matches against Djokovic.

"I am so ecstatic right now, so happy and that's about it.

"I think that today I played the break points really well. Every time he had a break point I was able to come up with a big serve. And in the end I just fought the tiebreak and got a couple of loose errors and that was it."

After initial nerves on Saturday, Querrey showed great composure, saving 11 out of 12 break points in the fourth set, several with aces, as Djokovic tried everything to take the match into a deciding set.

It looked as though the pressure had told when he dropped serve in the ninth game, but he re-grouped immediately and brought up two break points with a stunning backhand pass.

Djokovic saved the first but scooped a low volley into the net to huge cheers from the crowd.

Querrey held serve before rain returned with Djokovic serving to stay alive. But it could not douse Querrey's fighting spirit as he battled back from 3-1 down in the tiebreak to complete his first victory over a current world number one.

"I had my chances," said Djokovic who confirmed he would not play in the Davis Cup quarterfinal against Britain this month.

"I just wasn't feeling the ball as well as I wished."