Novak Djokovic needed a fraction short of five hours to see off Marcos Baghdatis and reach his first Wimbledon semi-final.

The Serbian fourth seed won the first two sets on tie-breaks but Baghdatis, who reached the last four 12 months ago, hit back to take the next two and force a decider.

Four hours and 59 minutes after they stepped out onto Court One, Djokovic earned the first match points and a netted forehand from his opponent gave him a 7-6 7-6 6-7 4-6 7-5 success.

Along the way Djokovic required treatment for a stiff back and in the final set he looked physically drained, yet he still managed to find the reserves to break Baghdatis in the 11th game to set up his chance of victory.

He will meet Rafael Nadal in Saturday's semi-final after the second seed won in straight sets against Tomas Berdych earlier in the day.

Djokovic was clearly exhausted after his exertions and he concedes it will be difficult to pick himself up for his match against the second seed.

Djokovic said: "If you are playing a five-hour match and a

four-and-a-half-hour match yesterday, I even don't know how I managed to hold on and get to the semi-finals.

"Right now I feel pretty exhausted and tired. When you play long matches with

guys like Hewitt and Baghdatis - nine and a half hours in two days - then if

you're human, your fitness is not right, that's for sure. Now I'm really trying to recover and then get ready for the next one.''

Were Djokovic to upset the applecart and defeat Nadal in the semis, he would

turn out for a seventh day in succession in Sunday's final - a huge ask for such

an inexperienced campaigner.

"Unfortunately this year the weather has been a big problem and the schedule

[has meant] that I have to play every day,'' he added.

"From the start of the tournament I don't know if I had one day off. Maybe

one or two, but basically I was on the schedule every day.

"That is not encouraging for the semi-final. But he [Nadal] was kind of in

that situation as well, even though of course he spent much less hours than me

on the court.

"He's physically probably the most prepared player in the world. But I'll try

to do my best and recover.

"Nadal is a baseline player who is a very strong, big competitor. He has

mental strength like Hewitt because they both play every point. They fight for

every point like it's match point.

"I can't expect a lot of easy points from him.''