Andy Roddick is an itchy, twitchy guy. Sitting still isn't easy. He has been growing a beard during this Wimbledon fortnight, a scraggly thing that makes Roddick seem an unfinished product, a man still dangling a foot in teenage life.

His tennis game, though, has grown up.

Roddick used to be an itchy, twitchy guy on the tennis court too. He jumped around between points and when he hit a tennis ball, his arms and legs had extra movement. It was as if he were a Slinky and his appendages moved in sections. When the nerves began, he sprayed his shots. This Roddick was also impatient. Waiting two or three shots before trying to hit a winner did not suit him. Now, Roddick is 21 and he has won a major title, the 2003 U.S. Open. As he has progressed through this Wimbledon without losing a set, Roddick has proved he is all grown up.

He played Saturday against Mario Ancic in the completion of a suspended semifinal and seemed destined to a meeting in the final with top seed Roger Federer.

Said Sjeng Schalken after Roddick had knocked the Dutchman out of the tournament in the quarterfinals, "The good thing he does, and he does it that much better than when I beat him one time -- that was three, four years ago -- he lets me play all my shots all the time and he's tough.

"When he used to play, he wanted to go for it a little bit more. But now, he's just going for it in the service game and the rest of the game is very solid. So he's doing very good."

If Roddick is serving, there is no holding him back. If the rally starts, Roddick doesn't have to win with the first big forehand. He doesn't have to go for broke. He's got game.

"It's a matter of experience," Roddick said. "Since last year's semi, I've played a lot of big matches, whether it be in the U.S. Open, the finals of the Masters Series events, matches where the No. 1 ranking is on the line. I've been in a lot more pressure situations and I think that helps."

Roddick, seeded second, is playing in his second straight Wimbledon semifinal. His opponent, 20-year-old Mario Ancic, ranked 63rd, is younger, less experienced, more impatient and proclaimed by former champion Boris Becker as the future, which apparently has arrived.

Roddick against Ancic figures to be an explosive display of power ball.

Ancic, a protege of newly retired Goran Ivanisevic, destroyed British joy in the men's event when he upset Tim Henman in the quarterfinals. He stands 6-feet-5, yet moves more quickly and gracefully around a tennis court than Ivanisevic did. Ancic nearly took out Andre Agassi at the French Open a year ago and he upset Federer here two years ago.

Ancic credited his service returns against Henman for his surprise quarterfinal win as much as his big serving.

Still, Ancic describes himself as a work in progress.

"I am still working on my kind of game," he said. "You know, an aggressive, attacking style. I think that's a good way to go."

Roddick beat Ancic three weeks ago in a Wimbledon warmup. It was three sets of bashing, smashing tennis and the final score, 7-6, 4-6, 6-4, was a good indication of the dominance of the serve.

"There wasn't much between us," Roddick said. "A lot of big serving."

At this point last year, Roddick was taken apart by the surgical precision of Federer. Since then, Roddick has won the U.S. Open and earned a No. 1 ranking.

The ranking was lost to Federer when the 22-year-old from Switzerland won the Australian Open, but Roddick has established himself as second best and on the rise.

It's happened because Roddick has learned to slow down.

"I've developed a sense of when to go for it and when not to," he said. "I play to my instinct. Like the other day against Alexander Popp, he was going for broke. So I figured, 'OK, let's make him play as much as possible and see if he can weather the storm. If he has peaks and valleys, I'll get the chance to break.

"[Against Schalken,] if I got a shot to really try to hit, I had to take it. Sjeng, he's not going to give you anything. So a lot of it has to do with matchups."

Roddick has figured that out too. Every day is different, especially when you slow down and pay attention.

"It's a matter of experience," says Andy Roddick of his marked improvement in allowing a point to develop rather than forcing situation too quickly by constantly going for winners. "I've developed a sense of when to go for it and when not to. I play to my instinct," says Andy Roddick, who is rapidly developing a dangerous understanding of patience to go with his game's already overwhelming power.