Tennis Wimbledon Championships: It was a mildly comic script with a lethal twist at the end. If it were to be stripped to the bone and billed in neon lights around Leicester Square it would go something like "Giant man Ivo Karlovic beats Champion small guy Lleyton Hewitt."

Roaming the Centre Court grass like a long-legged creature from the Serengeti, all legs and a centre of gravity so high that it promised a terrific tumble at some stage of the match, the 203rd-ranked player in the world, who had to play three matches in a pre-Wimbledon tournament in Roehampton just to step through the gates, made his first Grand Slam match not just memorable but historic.

Karlovic, at 6ft 10in the tallest man to play at Wimbledon, may have the awkward, swaying movement of a long-necked quadruped, but yesterday, against the Australian number one seed and defending champion, Karlovic imposed his limited but highly effective game of swat and volley.

Not since Spanish top seed and holder of the title Manuel Santana lost in the first round to Charlie Pasarell in 1967 has there been a bigger upset in the men's singles draw.

And upset Hewitt was. Few people can fulminate like the 22-year-old, although this time philosophy replaced his traditional vituperation. Grabbing such a footnote in tennis history was not part of this year's design and Hewitt made his departure a little stunned and not in the manner of the pit bull that had yapped and nipped through the first set, threatening to savage his unsteady opponent.

"I'd never seen him play. I'd seen him walk around a bit before. Knew he had a big serve and that was obviously his big weapon," said Hewitt. "You know, I just didn't take my chances."

That opening act set up what was to be a bogus plot in the drama as Hewitt rushed to a 6-1 lead, suggesting that he would topple his opponent in three sets. The stage-struck Karlovic was unable to keep a ball in play.

"The first (set) I was completely scared," he said. "After I saw that I could beat him, I started to play more better. I mean it was a bit lucky. But that's life."

Like Santana, Hewitt finally went out in four sets 1-6, 7-6(7-5), 6-3, 6-4, but unlike Santana the Australian buckled to a player who had just emerged from the tennis primordial goo, an unknown voyager from the dark edges of the sport with no track record and given faint hope of advancing past the £8,630 first stage of the event.

But the 24-year-old from Zagreb had a tactic and stuck to it by using his height to put angles on serves that one of the world's best returners could not reach. Time after time Hewitt put a racquet on the ball, but given the severe angles Karlovic was able to ping it out towards the photographers' pit, his frustration grew.

Hewitt let slip a possible 2-0 lead in the second set, as he led 15-40. Then, at 2-1 up in the same set, again let go a love-40 lead to invite Karlovic back into the match.

That gave the qualifier hope and his serve became more accurate. The newly confident Karlovic began to win almost 70 per cent of his service points. Over the four sets, almost half of his serves, 49 per cent, could not be returned by Hewitt.

"At the end of the day I'd be disappointed losing Wimbledon first round. It's what you've got to deal with," said Hewitt.

"It is very hard at the moment to try and say you're going to try and learn something from it, but hopefully I can. When I look back at it, I'll probably have a clearer mind, see where things went wrong and where, hopefully, I can improve in the future.

"At the moment it's pretty disappointing. I've had some losses that probably stick around. I'm sure this one is not going to go away by the end of the week."

Given the desire of most athletes to live in a controlled environment, it was suggested that Hewitt's changes to his off-court life might have affected what he was trying to do on court.

He is involved in a lawsuit against the players' body, the ATP (Association of Tennis Professionals) for a €20,000 fine imposed for not undertaking a mandatory television interview with ESPN, the US network which has the contract for the American satellite broadcasts of Wimbledon.

In recent weeks he also sacked his coach, Jason Stoltenberg.

"Not at all," was his dismissive reply to whether those issues had affected him.

"As the match went on he got better and better. If I could have kept on top of him, kept pounding him into the ground, I could have broken down his serve maybe a little bit more and got to look at a few more second serves."

It was a tiebreak that gave Karlovic his opportunity. Had Hewitt gone two sets ahead, there was little chance of the debutant having the reserves to claw back into the match. Even for abrasive fighters such as Andre Agassi, coming back from 2-0 down is arduous and an unusual demand on energy reserves and concentration.

But from a set apiece even the nervousness had dissipated and Karlovic began to blossom. Holding a break in the fourth game, he then served out the set for 2-1 and continued to force the champion back and wide.

In the final set, he struck in game five, jumping on a weak Hewitt service game to go 5-4. By then it was academic, as Karlovic bombed Hewitt, earning three match points and the match.

Thus he continued the quaint Croatian tradition of upsetting the odds. Last year the unknown Marion Ancic defeated Roger Federer, while Goran Ivanisevic won an emotional 2001 title by beating Australia's Pat Rafter in the final.

Andy Roddick is now 11/4 favourite to win Wimbledon with William Hill - who make Tim Henman fourth and Greg Rusedski sixth favourites. Hills make Agassi 100/30 second favourite and also offer 5/1 Federer; 8/1 Henman; 16/1 Philipoussis; 20/1 Rusedski; 25/1 Schalken.