Rafael Nadal believes Novak Djokovic is once again playing at his highest level, after suffering defeat to the Serbian in a magnificent Wimbledon semifinal.

Djokovic has endured a difficult two years since completing a career Grand Slam at the 2016 French Open, his only subsequent major final appearance until this weekend coming at the same year's US Open.

The Serbian – now ranked 21st in the world – has been dogged by injuries and made multiple changes to his backroom team, but produced one of his finest performances to see off Nadal 6-4 3-6 7-6 (11-9) 3-6 10-8 in five hours and 15 minutes across two days under the Centre Court roof and earn a shot at a 13th grand slam title.

For world number one Nadal, the match provided clear evidence that Djokovic is reaching his previous heights.

"He's playing great. My opinion, he's playing at his top level again," said Nadal.

"He's in the final of Wimbledon. You can't be in the final of Wimbledon, even if your name is Novak Djokovic, without playing a great level of tennis."

"I think it was a fantastic level of tennis for both of us. I was not a spectator, but I think was a great show for the fans."

"Of course, I'm not happy with the final result. [But I'm] happy about being part of this match that has been a great one."

It was the 52nd meeting between the two players and Djokovic's victory gave him a 27-25 lead in their head-to-head.

On the task that Djokovic presents, Nadal said: "The biggest challenge is I am playing against one of the best players of the history. Probably for him it's something similar."

"The respect is very high because he is an opponent that I've played a lot of times. We played in the greatest stadiums, greatest moments for both of us. We shared on court a lot of big moments for both of us."

"He is a great rival. This was another battle that stays there."