The Spanish second seed, the runner-up to Roger Federer in 2006, triumphed 4-6, 3-6, 6-1, 6-2, 6-2 in an enthralling three-hour contest and will now face seventh seed Tomas Berdych of the Czech Republic for a place in the semifinals.

In another enthralling encounter, Serbian teenager Novak Djokovic overcame his more illustrious opponent Lleyton Hewitt to set up a semifinal encounter against Marcos Baghdatis of Cyprus.

On Court Two, the so-called graveyard of the champions where Nadal had been relegated for the day, it was the 14th seeded Russian who looked set to play the role as undertaker to the Spaniard's Wimbledon dream.

The 25-year-old Youzhny had defeated the Spaniard in the quarterfinals of the US Open last year and he was virtually untroubled in the first two sets on Thursday wrapping up the opener in just 36 minutes and then grabbing an early break in the second.

He was two sets up after 81 minutes when Nadal went long with a backhand.

The world number two had failed to carve out a single break point in those two sets, but he was unstoppable in the third breaking in the second and sixth games to reduce the deficit.

Youzhny needed treatment during the changeover for a back injury and his movement became more restricted as Nadal seized his opportunity to level the match at two sets apiece with breaks in the third and seventh games of the fourth set.

The Russian needed another bout of treatment for his injury and tried to calm himself by leaving a packed court for a toilet break.

But it was to no avail as Nadal broke in the third and fifth games of the final set to lead 4-1 against an exhausted opponent.

Nadal served a love game to go to 5-1 before Youzhny saved a match point in the seventh game.

But there was no reprieve in the next game with the Spaniard taking the tie with a vicious crosscourt forehand.

Serbian fourth seed Novak Djokovic overcame a back injury as well as the famed fighting spirit of former champion Lleyton Hewitt to reach the Wimbledon quarterfinals on in a four-hour thriller.

The 20-year-old clinched a 7-6 (10/8), 7-6 (7/2), 4-6, 7-6 (7/5) win over the 16th seeded Australian and will take on Cypriot 10th seed Marcos Baghdatis for a place in the semifinal.

The defeat was Hewitt's earliest exit from the All England Club since 2003 when he was a shock first round casualty as defending champion.

But on Thursday he played his part in a memorable feast of big-hitting and marathon rallies against the Serbian player who is being tipped as a future Grand Slam winner.

The first set took an hour to complete with one point in the tiebreak lasting a gruelling 40 strokes. Hewitt had two set points in the breaker but Djokovic saved them both.

The fourth seed then wrapped up the opener on his third set point when Hewitt hit long.

The battling Australian had won the pair's only previous clash at the US Open in 2006 but the young Serb has made great strides in his career since then.

He won his first Masters event in Miami, taking his career total to five, was also a semifinalist at the French Open and went to four in the world.

Djokovic used that new self-confidence to take the second set tiebreak.

But Hewitt, the king of lost causes, reduced the deficit by sweeping up the third set before Djokovic called an injury time-out for treatment on a back injury.

In a tense fourth set, the players exchanged breaks in the third and fourth games before Hewitt edged ahead with another break to lead 5-4.

But serving for the set, he fell apart.

Djokovic hit back to level and then edged ahead to 6-5 before the third tiebreak beckoned.

The Serb took the tie on his third match point when Hewitt dumped a backhand into the net.