Murray went out to Nalbandian (Getty).

Heroic Andy Murray slipped to an agonising five-set defeat against 18th seed David Nalbandian in a true Centre Court epic on Saturday.

The 18-year-old Scot finished the three-hour, 13-minute match stricken by exhaustion and injury as the Argentinian triumphed 6-7 1-6 6-0 6-4 6-1.

Nalbandian's sheer consistency sent him into the fourth round, but the abiding memory will be of how Murray came so close to fashioning one of the greatest victories in British tennis history.

Two-time former women's champion Serena Williams suffered a shock third-round exit at the hands of unseeded Jill Craybas.

Serena, hoping to set up a meeting with sister Venus in the last 16, went down in straight sets in the gathering gloom on Court Two.

Craybas took the first set 6-3 and though the second went to a tie-break, she held her nerve to take it 7-4 and clinch a famous victory.

Defending champion Roger Federer dropped his first set of the week but stayed on course to complete a hat-trick of men's titles when he overcame stubborn resistance from Nicolas Kiefer.

The world number one lost a tie-break and twice dropped his serve in the fourth set but they were only minor hiccups as he gained a 6-2 6-7 6-1 7-5 third-round victory in two hours and 35 minutes to extend his winning run on grass to 32 matches.

Federer will now meet former French Open champion Juan Carlos Ferrero, who came from a set down to beat another German, Florian Mayer, 3-6 6-2 6-1 6-1.

Second seed Andy Roddick, who needed five sets and two days to beat lucky loser Daniele Bracciali in the last round, was on court for under two hours against little-known Russian Igor Andreev.

The American took just an hour to wrap up the first two sets but encountered stiffer resistance before clinching a 6-2 6-2 7-6 victory.

Andreev, who had to have court-side treatment in the third set, saved a match point to force a tie-break, which Roddick took 7-4.

Roddick will now face Argentine 15th seed Guillermo Coria, who came from two sets down to beat Jurgen Melzer of Austria.

Dmitry Tursunov, the man who ended the Wimbledon dream of Tim Henman, is also through to the last 16.

The 22-year-old unseeded Russian gained a 5-7 7-6 6-2 6-2 over Germany's Alexander Popp in the third round to set up a meeting with Frenchman Sebastien Grosjean, who knocked Henman out at the quarter-final stage two years ago.

Tursunov, who has a protected ranking of 76 after being plagued by a back injury, came from a set down to secure a place in the last 16 of a Grand-Slam event for the first time in his career.

Grass expert Grosjean - a Wimbledon semi-finalist in each of the last two years - beat qualifier Novak Djokovic of Serbia and Montenegro 7-5 6-4 5-7 6-4.

Like Ferrero, Max Mirnyi of Belarus equalled his best showing at Wimbledon with a 5-7 7-5 6-4 7-6 victory over 28th seed Jiri Novak, of the Czech Republic.

The 27-year-old, who reached the final at Nottingham a week ago, claimed the 201st win of his career to set up a meeting with 12th seed Thomas Johansson, who despatched Janko Tipsarevic 6-2 6-3 6-1.

In the day's other men's third-round match the 31st seed Mikhail Youzhny beat Jonas Bjorkman in four sets.

Back in the women's singles defending champion Maria Sharapova slugged her way through to the last 16 but stubborn Katarina Srebotnik made her work as the Russian champion dropped her serve for the first time before winning 6-2 6-4 on Court One.

The Slovenian, ranked 57 in the world, drove the number two seed into the kind of errors that punctuated her play throughout last week's title defence at Birmingham.

Sharapova contributed to her own struggles which kept her on court for an hour and 31 minutes - by far her longest contest of these championships.

Number One seed Lindsay Davenport was in a hurry to get through her rain-delayed third-round clash with Russia's Dinara Safina on Court Two.

The 1999 Wimbledon champion had been scheduled to be the last match on Court One on Friday, only for thundery downpours to halt play at the All England Club for the first time this week.

However the unscheduled extra rest seemed to do her the power of good as she blitzed the hapless Safina 6-2 6-1.

Former champion Venus Williams went one better than beaten sister Serena with a hard-fought victory over Daniela Hantuchova. She won 7-5 6-3.

Elsewhere French Open finalist Mary Pierce blitzed 17-year-old Serbian prospect Ana Ivanovic to win a place in the last 16.

Despite toiling in her previous match, Pierce looked a different animal here, using all her finesse and experience to carve out a 6-1 6-4 win.

In the bottom half of the draw, former champion Conchita Martinez was beaten in straight sets by Czech Kveta Peschke.

Peschke, 29, continued her comeback from two lots of knee surgery with a 6-4 6-1 victory over the 1994 champion.

Nadia Petrova shrugged off the challenge of Cara Black to progress.

The Russian, seeded eight this year, served well throughout and was good value for her victory.

Petrova's win means she has now equalled her best ever showing at SW19 after she reached round four last year.