Safin, 28, twice a Grand Slam winner but now a lowly 75 in the world rankings, managed to keep his febrile temperament in check and refused to be denied against the 31st seed.

He confessed afterwards: “I started a little bit nervous as I have never beaten him in a big tournament.”

In a rain-interrupted first set, Lopez was quick to seize the initiative and, in his only outburst of the match, an exasperated Safin sent one ball hurtling over the roof and out of the court.

“I was too nervous to play well at the beginning,” said Safin who welcomed the rain break of more than two hours so he could calm down.

By contrast Lopez, he said, had “a good forehand, good slice, good serve and was full of confidence.”

But the lanky Russian, a quarter-finalist at Wimbledon in 2001, fought back with much of the power, flair and fluid ground strokes that made him world number one back in 2000. Safin, who knocked out third seed Novak Djokovic in the second round, took the next three sets with a fine attacking game to earn a crack at five-time champion Roger Federer in the semi-finals.

The match clearly gave Safin immense satisfaction that his undoubted talent had risen to the surface once more.

“I come up a few steps in the ranks,” he said. “I am back in the top 50 which is great. Whatever I do against Roger, it has been a great two weeks,” he concluded.

Federer, meanwhile, snuffed out the challenge of the last man to beat him on grass with a 6-1, 7-5, 6-4 victory over Mario Ancic.

The Croat, then 18, upset Federer in the first round on his Wimbledon debut in 2002. Since then the Swiss has won 64 consecutive matches on grass, 39 at the London Grand Slam where he has lifted the trophy five times in a row.

World number one Federer, in devastating form from the start, allowed Ancic only one point in his first four service games as he ran away with the opening set. Ancic improved after a rain delay lasting two hours and 13 minutes with the score 1-1 in the second set, playing a full part in some high quality rallies. Games went with serve until the 11th when the 1.95-metre tall Croat netted a volley to give his opponent the break point.

Federer was in full flow in the third set and won the match in one hour and 41 minutes on his first match point.