They say that Andy Roddick has gotten bigger since the French Open two weeks ago, physically, mentally, his stature, his aura. The person least likely to dispute that claim is the 11th seed Thomas Johansson, who came to Wimbledon looking for his 12th straight win on grass and departed knowing that he had just been dumped by the most talented American teenager to emerge in the last decade.

Roddick, still 18 years old, had image before coming to London of a bull at the gate, a scatter gun big hitter who lacked the calibration and levity to arrive at the championships and take scalps.

His phenomenal serve, regularly surpassing the 130 mph mark, is now on the record books at Rolland Garros as the most successful serve since statistics began in 1991. In his second-round defeat of Michael Chang onthe clay this year he delivered 37 acres, more than anyone else in the last 10 years.

But Roddick has brought something more than power to Wimbledon. Infectious, occasionally rash in his enthusiasm and possessing a wonderful touch at the net and the ability to bring a buzz to centre court, there has been nothing like him around the event since the blond-streaked Andre Agassi emerged as some glorious punk warrior from Vegas almost 10 years ago.

While Johansson contrived his own difficulties in the crucial two tie breaks in the first and fourth sets, Roddick never appeared anything less than fearlessly dangerous, not only serving down 'some major heat' as the American like to describe it, but rattling the Swede on his serve and tormenting him from back court.

Johansson's nerve vapourised in the first set tiebreak, Roddick allowing him only one point for an astonishing 7-1. That discouraging lapse seemed to stay with the Swede for a shambles of a second set as Roddick sensed the dip and frustration and set about him for 6-1.

At the stage the match could have deteriorated into a showboating display of big winners and crowd pleasing, risky missiles from Roddick but Johansson, to his credit, had the awareness to hang tough.

He had come into the tournament on his longest winning streak for over four years and was expected to teach the former world junior champion a lesson on the unfamiliar surface.

Roddick, the youngest player remaining in the draw, had played his first career match on grass two weeks ago at Queens having ended his junior career only seven months ago in December 2000.

Refusing to stand on ceremony in his first extraordinary senior season he proceeded to win his debutant tour-level event on clay in Atlanta before assembling a 12-match winning streak by following that up with another title a week later in Houston.

Johansson broke back once for 6-4 in the third to take the match to a fourth set and again it went with service. Although Roddick's backhand was wavering, it was again forced to a second tiebreak.

Once more Johansson's serving edge failed him. Despite hitting 25 aces overall, the teenager took a 4-1 lead before pressing home for the set 7-3 and the match.

"I like playing in these type of situations rather than with no one watching," said Roddick reacting to his first time on Centre Court, "I play better. I mean it's like a place like Wrigley Field or Fenway Park or something. It's just kind of majestic. It's the most prestigious place to play. To get such a chance at such a young age, I really cherish that.

"I played the early points pretty good in the tiebreaks. Apart from a double fault I played them pretty flawlessly. It's great now to play Goran (Icanisevic) in the next round. I got to play Michael Chang in Paris, now it's Goran. That's great.

"I'm definitely just learning the ins and outs, what shots to go for at what times. I'm still going with the flow," he said.[P}Pete Sampras, as expected, put an end to local hope Barry Cowan, a wildcard entry. It was set-up to be a matter of Cowan departing with dignity, which for the first two sets seemed just so. But winning a tie break in the third and gaining inspiration in the fourth to break the Sampras serve, Cowan then took the defending champion directly to a place he did not want to go.

Cowan, who listened to the Liverpool football theme at changeovers and who had been playing in challenger events all year, had not had a win at Wimbledon for five years. He had only ever played in seven Grand Slam events compared to Sampras's 48 but clearly he caught the American in uncertain form.

Demonstrating the composure of a player with nothing at all to lose, the match, from the Sampras viewpoint , ominously spiralled forwards as Cowan broke him in the fourth and with vocal home support happily took the best grasscourt player in history into an evening fifth set.

An upset would have been one of the biggest in the history of the championship and clearly Sampras was aware. It was only in the fifth that he warned to the task, nervously picking up his game immediately and racing to a 4-0 lead.

But again Cowan suggested that another twist might creep in and after another series of majestic returns on the Sampras serve, he broke back for 1-4. He continued to threaten the Sampras serve with a further two breaks points, forcing the champion to save with two aces on each one.

Finally, serving for the match at 5-3 the Sampras serve held. A sweaty 6-3, 6-2, 6-7, 4-6, 6-3 but home and dry.