LONDON (REUTERS) - Rafael Nadal struggled to hide his disappointment after his attempt to reclaim the Wimbledon crown he last won seven years ago fell apart at the hands of Gilles Muller on Monday (July 10), going down 6-3, 6-4, 3-6, 4-6, 15-13 in a fourth-round classic.

The 31-year-old Spaniard had rolled back the years in reaching the fourth round and seemed in the mood, and form, for a serious title assault at the All England Club just weeks after winning the French Open for the 10th time.

But left-handed Luxembourger Muller, seeded 16th, had other ideas and clinched an epic fifth set 15-13 after Nadal had staved off four match points in a thrilling climax.

Twelve years after first getting the better of Nadal on the All England Club lawns, Muller stood firm in the 135-minute fifth set.

Nine times in that heart-pounding decider, 31-year-old French Open champion Nadal served to stay alive. Men of lesser resolve than the 34-year-old Muller would have cracked - but the left-handed serve-and-volleyer was relentless in pursuit of victory and it was Nadal who succumbed when asked to walk the tightrope for the 10th time at 13-14.

A mis-hit forehand gave Muller two more match points and this time there was no escape for Nadal as another error off his trusty weapon ballooned over the baseline.

Muller stood motionless for a few seconds, taking in the enormity of his victory as the Court One crowd which had spent the past two hours on the edge of their seats, rose as one.

There was little doubt he deserved the ovation. He outplayed Nadal in the opening two sets and then, after weathering a ferocious fightback, made the running in the fifth when his baseline craft matched Nadal's. He struck 30 aces and 95 winners as he moved on to a quarter-final with Marin Cilic - his second in the Slams after reaching the last eight at the 2008 US Open.

"I'm just glad it's over," said Muller, who was cheered on from the stands by Prince Felix of Luxembourg.

"I did really well in the first two sets, then Rafa stepped it up. It was a big battle. When I had the last two match points, I thought I just had to give it a shot.

"Somehow in the end I made it."

Magnanimous as ever, 15-time Grand Slam champion Nadal made no excuses, admitting Muller was the better player, but said he had wasted a golden opportunity to go all the way.

"I had my chances, and he had some mistakes, but not enough," former world No. 1 Nadal, who returned to form at the start of the year when reaching the Australian Open final, told reporters.

"Is true most of the time in the fifth set he played more aggressive and he played better than me.

"I played well for moments, but I was a lot of times fighting against the score, too many times in the fifth. "Finally, the normal thing when you are in the situation too many times, is finally you lose. That's what happened.

"It's not the result that I was expecting. I played better than other years, true. At the same time I was ready for important things, so I lost an opportunity."

Until Monday, Nadal had not lost a set in Grand Slam action since losing January's Melbourne Park final to Roger Federer.

However, this was not to be his day.

He had thumped his head on a ceiling while limbering up in a corridor before the start of play, appeared to turn his ankle slightly in the third set and was blinded by the sinking sun glinting against part of the Court One structure deep in the fifth set as he desperately tried to fight Muller off.

Ultimately, he paid for losing the first two sets 3-6, 4-6 and while he hit back impressively to win the next two by the same margin, he was unable to complete what would have been only his fourth recovery from two sets down.

"When you play against these kind of players, you cannot have mistakes with yourself. That's what I did. I did twice, in the first and in the second. That cost me two sets," he said. "In the fifth, he had more chances than me. So maybe he deserve it a little more than me."