I came across this interesting article from 1999 that mentions Guille quite a bit. Here is a partial cut and paste of the article with the Guille bits:
New World Order--Orange Bowl
It's a second-round match in the boys' 18-and-under division of the 1998 Rado Orange Bowl International Tennis Championships, and Zack Fleishman, an 18-year-old American, is giving one of the most promising juniors in the world, 16-year-old Guillermo Coria of Argentina, all he can handle. The score is 4-4 in the first set.
Fleishman is a sturdy chunk of Southern California beefcake, 6-foot-2 and 175 pounds, with wolfish gray eyes and dyed patches of blond in his hair. His opponent is a bandy-legged, beady-eyed mixture of the impish and the world-weary. Strands of his long, stringy brown hair stream out of a cap that's pulled tight to his brow.
When Coria, the No. 6 seed, takes the first set 6-4, a bipartisan wave of applause rises from the scattering of spectators and tennis insiders seated in the bleachers. Most are aware that the differences between the two players go much deeper than mere appearance.
Fleishman, a college freshman, plays for UCLA. The face of his racquet is stenciled with a homemade red, white, and blue motif, and his tennis shoes are well-worn. To be eligible to play college tennis and receive an athletic scholarship, Fleishman has had to observe the regulations governing amateur status as stipulated by the National Collegiate Athletic Association. He has never taken a dime from an agent, a tournament director, or a clothing company.
The same cannot be said of Coria, who is already a professional in everything but name. He's impeccably attired in fresh-from-the-box Adidas clothing and shoes. And he has something that most gifted athletes his age can only fantasize about
: a seven-figure endorsement deal and a savvy agent who looks out for his every need.
Coria is one of the new breed of junior tennis player that has emerged from Latin America and Europe in recent years. It's this player, groomed for success from a tender age, that not only dominates today's pro tours, but also makes born-and-bred U.S. champions an endangered species.
And right now, as he begins to blow holes in Fleishman's defenses, Coria looks to be the more likely candidate for professional stardom. Relaxing in the bleachers, Coria's agent, Patricio Apey Jr., of the giant sports-management company ProServ, is clearly pleased by the way his young client is handling the pressure of ''playing up'' (Coria, the 1997 Orange Bowl 16s champion, is still eligible in the lower age division).
Coria breaks Fleishman to take a 4-1 lead in the second set. Although he stands only 5-foot-9 and weighs 145 pounds sopping wet, Coria uses what a pitching coach in baseball would call a ''live arm'' to generate his powerful ground strokes, and he's tremendously fleet afoot. In fact, Coria, a small-town boy from Venado Tuerto, deep in the heart of soccer country, might easily have wound up playing his nation's most popular sport for a living.
''I come from the same town as the soccer star [Gabriel] Batistuta,'' he says in broken English. ''My dream was to play for the Rio Plata [soccer] club, but my father, Oscar, is a tennis teacher who taught me to prefer tennis.''
By the age of 14, Coria was firmly tucked under Apey's wing. But rather than cash in too early, Apey resisted endorsement offers until Coria had a breakthrough year in 1998, winning the Milano (Italy) 18s and sparking a four-firm bidding war that culminated in a five-year deal with Adidas.
''I was hoping Guillermo would peak in the juniors at age 16, so I could make him a deal that would carry him through that next, difficult step up to the pro tour,'' says Apey. ''If you exercise some restraint and good timing, you can make decisions that take pressure off a kid instead of piling it on him.''
At match point, Coria hits a frozen rope of a forehand down the line to close Fleishman out 6-2. He ambles to the net, a tight but arresting smile on his chiseled face. Among the throng of dispersing fans are three disappointed coaches from the USTA development program: Craig Kardon, Joey Rive, and Eliot Teltscher.
Coria would go on to reach the Orange Bowl finals before losing to Roger Federer, a rising star from Switzerland.
Entire article can be found here: