PARIS (Reuters) - Andre Agassi, Pete Sampras, and Michael Chang are convinced.

So are the sponsors and marketing gurus lined up at the Roland Garros gates, contracts in hand.

Everyone from Paris to New York, it seems, agrees Andy Roddick is the real deal -- the new standard-bearer for American men's tennis -- and that was even before his courageous second-round win over Chang at the French Open on Wednesday.

While Agassi, Sampras and Chang are not yet quite ready to pass the torch to the 18-year-old Roddick, the aging icons have anointed the teenager as their heir apparent, the next great American champion.

``Roddick I think has got an unbelievable future,'' said Sampras, who knows something about winning, having claimed a record 13 Grand Slam titles. ``You look at the young guys coming up, American guys, he's got the biggest weapon of anyone with the big serve.

``He's got a lot of potential. I think he's the next up and coming young American we have.''

With Agassi's brashness now replaced by caution and Sampras's confidence shaken in recent years, Roddick brings a refreshing attitude to the French Open that has not been seen since, well, Agassi and Sampras were teenagers in Paris.

Backed up by a howitzer 140mph serve and an unbeaten record on clay, Roddick strolled into Roland Garros for his opening match on Monday with a cocky confidence that has been the hallmark of past American champions.

BACK-TO-BACK TITLES

He has 12 claycourt wins this season, almost three times as many as Sampras and Agassi combined, which have earned him back-to-back titles in Atlanta and Houston.

The world junior champion and last year's French Open junior finalist, also has a growing list of big scalps that includes Sampras, former world number one Marcelo Rios and experienced American Todd Martin .

``I've always liked his game,'' said Agassi, who has occasionally visited Roddick at his Florida home for chats and private practice sessions. ``I think his game has some tremendous weapons. I think he's better than a lot of guys.

``I think one thing that it's done is show me that he is ready to win at an early age."

``That's always good to see. Even though they're not big tournaments, they're still wins."

``It's not easy to win when you haven't done it before. It surprised me that he won so early but it's a long road."

``He's coming along after what has been one of the most accomplished group of Americans that we've ever had come through at one time and that's going to be a lot of pressure."

``I think he can handle it but it's a high standard.''

FALSE DAWNS

Americans have been fooled by many false dawns.

Agassi, Sampras, Chang and Jim Courier, Grand Slam winners all, more than filled the void left by Jimmy Connors and John McEnroe.

But as flecks of gray begin to appear on the receding hairlines of the current guard, no player, until now, has appeared capable of filling those soon-to-be vacant sneakers.

``I have seen somebody who can rise to the heights attained by Pete and Andre -- and his name is Andy Roddick,'' said American Davis Cup captain Patrick McEnroe, another member of Roddick's growing fan club.

While the 18-year-old Roddick has made it clear he's prepared for the challenge, he is equally emphatic that he does not want the job right away.

``I don't feel any pressure about being the next great American,'' said Roddick, already a media darling, squired around the late night talk circuit, including the David Letterman show, following his victory at the U.S. claycourt championships. ``Any expectation that I'm going to do what those guys did just isn't smart.

``They were probably the greatest group of guys from one country ever to play in the same generation.

BIG HEART

Blessed with one of the game's most menacing serves and punishing power, Roddick also confirmed he has the heart of champion.

The teenager firmly established his credentials on Wednesday, when he reached the third round at Roland Garros, battling past Chang in one of the bravest efforts ever witnessed on a tennis court.

In a contest tinged with poignant coincidences, a courageous Roddick finished the four-hour marathon wincing in pain from cramps, barely able to stand, occasionally using his racket as a walking stick.

``He has an enormous heart, he's a gladiator,'' said Roddick's coach Tarik Benhabiles. ``He could have carried on like that until 20 games all.''