Wimbledon: Monday 23 June to Sunday 6 July
Coverage: BBC TV, BBCi, Radio 5 Live and the BBC Sport website.
Nalbandian had never previously fallen before the round of 32 at Wimbledon
Men's seventh seed David Nalbandian was sent crashing out of Wimbledon on day one of the championships by world number 95 Frank Dancevic of Canada.
The Argentine, who lost to Lleyton Hewitt in the 2002 final, was dominated by 23-year-old Dancevic throughout and lost 6-4 6-2 6-4 in just 96 minutes.
Hewitt, seeded 20th, was given a stern test before beating Dutchman Robin Haase 6-7 (4-7) 6-3 6-3 6-7 (1-7) 6-2.
But 18th seed Ivo Karlovic lost 6-4 6-7 (7-4) 3-6 5-7 to Simon Stadler.
The unseeded German, ranked 172 in the world, converted one break point in the third set and another in the fourth to send the Croatian tumbling.
Karlovic had been tipped to reach the latter rounds following his triumph at the Nottingham Open but, despite sending down 23 aces, his 29 unforced errors proved costly.
Nalbandian suffered a first-round defeat for the first time in six visits to SW19 and only the second time in 27 Grand Slam appearances.
"I didn't play well but tried and everything I missed, I missed narrowly. I expected better than this for sure," said the 26-year-old, who suggested he may have been carrying an undisclosed injury but refused to use it as an excuse.
Dancevic won the Surbiton Challenger on grass as a qualifier but was then forced to retire from his first round match at Queen's the following week with a wrist injury.
"This is one of the best victories of my career," he said. "With my wrist, I was just happy to play here. Today's a really big win for me, I'm really excited.
"I really was not expecting to win in straight sets. I had to take my chances and I got a break up early in each set and he looked a little shaky from the beginning."
The number 30 seed Gael Monfils bowed out of Wimbledon before a ball was hit.
The 21-year-old Frenchman was due to play Chris Guccione but withdrew from SW19 with a right shoulder injury.
Monfils was replaced by Serbia's Ilia Bozoljac, who went on to beat Guccione in four sets.
"I'm sad but I know it's the right decision, to withdraw," said the French Open semi-finalist
Fifth seed David Ferrer raced into a two-set lead against Sergiy Stakhovsky before the Ukrainian retired at 7-6 (8-6) 6-3 1-3.
Also a beneficiary of an injury was Mario Ancic, the last man to beat Roger Federer at Wimbledon, who was leading 31st seed Michael Llodra 6-4 7-6 (9-7) 2-0 when the Frenchman quit.
Hewitt faces the Spaniard Albert Montanes for a place in round three
Hewitt who missed most of the clay-court season with a hip injury, looked some way from full fitness as he lost the first set to 21-year-old Haase.
The 20th seed could not hide his frustration as he struggled for consistency but made his experience tell to prevail 6-7 (4-7) 6-3 6-3 6-7 (1-7) 6-2 and next up is Albert Montanes, who stormed past Carlos Berlocq.
Marcos Baghdatis, seeded 10, moved into the second round with a 6-3 6-2 6-7 (5-7) 6-3 victory over Belgium's Steve Darcis.
The Cypriot broke once in the first set and twice in the second as he looked to be cruising past Belgium's Darcis.
After Darcis rallied to take the third set Baghdatis, a Wimbledon semi-finalist in 2006, broke early and decisively in the fourth to set up a tie with Thomas Johansson for a place in round three.
In a battle of two 33-year-olds, Sweden's Johansson lost the first two sets to Vince Spadea before mounting a stunning comeback to win 6-7 (10-8) 6-7 (7-5) 6-3 6-4 6-3.
Number 11 seed Tomas Berdych struggled for consistency throughout his tie against 20-year-old Evgeny Korolev, eventually seeing off the Russian, ranked 78 in the world, 4-6 6-1 6-4 3-6 7-5.
Chile's Fernando Gonzalez, the 15th seed, overcame Robby Ginepri 7-6 (7-3) 7-5 7-5 and now takes on Simone Bolelli after the Italian dispatched British wildcard Alex Bogdanovic in four sets.
Juan Carlos Ferrero, seeded 21, looked to be in trouble when he lost the first set against 20-year-old American Sam Querrey.
But the clay specialist battled back to prevail 2-6 6-4 6-4 6-4 and will now play the unseeded German Mischa Zverev, who beat Alexander Peya 6-3 6-4 6-4.
Ferrero's fellow Spaniard Feliciano Lopez joined him in round two by beating Brian Dabul of Argentina 7-6 (7-1) 3-6 6-3 6-4 and now plays Roko Karanusic, a straights-sets victor over Luis Horna.
Italy's Andreas Seppi was another seed (29) to lose his opening set, to Tobias Kamke, but he was rarely troubled thereafter and came through 5-7 6-3 6-2 6-4.
Progress was far smoother for Marat Safin, the two-time Grand Slam winner storming to a 6-1 6-2 7-6 (7-3) win against Fabio Fognini, which sets up an encounter with world number three Novak Djokovic.
The big-serving Swede Robin Soderling beat Kevin Kim 7-5 0-6 6-3 6-4 to set up a match against world number one Federer.