At the U.S. Open next week, probably under the lights of Arthur Ashe Stadium and probably in the first or second round, Andre Agassi, at age 36 and after 33 years in tennis, will say goodbye to a sport that might have died without him.

History books not yet written will label Pete Sampras as the best of all American tennis players, if not the best of every nation. John McEnroe will live on as the sport’s first true artist, a virtuoso of touch, agility, and reflexes who played the game in a way never before seen and never since replicated. It’s unlikely that anyone will match the indomitable spirit of Bjorn Borg, thrice a backto-back champion on the clay of the French Open and the lawns of Wimbledon. Even in the longevity department, Agassi comes up a little short: Both Jimmy Connors and Ivan Lendl won more than 1,000 matches (Agassi has 866), and they won more titles. So did Guillermo Vilas. Sampras, Lendl, Connors, McEnroe, Borg, and Roger Federer have spent more weeks as the no. 1 player in the world.

Among the game’s greats, Agassi, on paper, is in the middle of the pack. Compared to legends past and future, he ranks last in career winning percentage (please see chart). His record in Grand Slam finals is 8–7. And when Agassi did win a major title, he rarely did so over an exceptional opponent (his victims included Yevgeny Kafelnikov, Michael Stich, Todd Martin, Arnaud Clement, Rainer Schuettler, and Andrei Medvedev). He twice defeated Sampras at a Grand Slam, in a semifinal and final at the Australian Open, the first major of the season and the one where Sampras’s lack of offcourt training was most apparent.

Even Agassi would agree that he is not the best there ever was.He spent 18 years chasing Sampras and now Federer, with few victories dotting a canvas of defeats.

One day, however, he ought to be remembered as the most important tennis player in the sport’s history, no matter the number of his titles. Agassi reinvented himself — once a brash, ball-smashing, cheeseburger-loving teenager, then a burned out failure, then a consummate champion, and now a wise man of fitness, philanthropy, and fatherhood — and the sport of tennis, too.

For years, Agassi carried tennis along, filling stadiums with admiring teenagers and, later, aging fans looking for one more memory. Over those years, modern men’s tennis was born, a new kind of all-court game characterized by angles, spins, and astounding athleticism. It’s a beautiful style, best practiced by Federer but increasingly mimicked by men like Richard Gasquet, Marcos Baghdatis, and, to varying degrees, Rafael Nadal. Men’s tennis is interesting and artful today, more so than it has been since McEnroe’s era. This is Agassi’s legacy.

After Rod Laver, the men who came closest to the career Grand Slam were either dominant attackers — Sampras, Stefan Edberg, Boris Becker, McEnroe — or indefatigable baseliners like Lendl or Mats Wilander (all six won three of the four major tournaments in their careers). Sampras and McEnroe had their chances at the French Open, but their serve-and-volley offense could never quite carve through the clay of Roland Garros and its defensive-minded experts. Lendl, on the other hand, insisted on playing serve-and-volley at Wimbledon, never believing that he could solve the lawns from the backcourt.

Unlike most of his forebears, Agassi made every surface conform to his game (he added an Olympic gold medal to boot). His success derived from the obsessions and unconventional teaching methods of his father, who once was a boxer for the Iranian Olympic team. For Mike Agassi, the ultimate implement of instruction was a ball machine aimed at the feet of his young son, who was not allowed to step behind the baseline. As soon as the ball bounced, young Agassi would meet it head on, his stance open to save him that fraction of a second it took to make a full turn to the side.

Agassi is not a big man — 5-feet-11 inches, and 177 pounds — nor is he an incredibly gifted athlete. He’s pigeontoed and not terribly fast, and not too flexible, either. His timing, however, is unrivaled, and because of this he often dictated the pace of points against far more imposing opponents. By hitting the ball early with a semi-Western (think frying pan) grip and angling his shots every which way, Agassi controlled the middle of the court and watched as his foes scrambled about like so many dogs playing fetch.

Unlike his peers, Agassi did not have to change his tactics to win on grass or clay. He just had to hope that he had his best form, and that some other more dominant specialist (Sampras at Wimbledon or the unheralded clay-court expert Andres Gomez, who dumped Agassi in the 1990 French Open final) did not. No better example of his malleable tennis exists than his first major title, in 1992 at Wimbledon, where he defeated Becker and, in the final, the sport’s ultimate serving machine, Goran Ivanisevic.

If one were to draw lines between past and present greats in tennis, the original serve and volleyers would beget McEnroe, who would beget Edberg, Becker, and Sampras. Borg inspired the baseliners, and the switch to modern rackets from wood, in the 1980s, gave men like Lendl and Wilander the slightly wider frames they needed to add more topspin, and hence more control, to their increasingly powerful ground strokes. Agassi took this baseline game and transformed it, turning the long and sleepy rallies of yore into intense exchanges where ever-decreasing openings were exploited for winners.

While Federer, the world’s best player, idolized Becker and Edberg and most often finds his mug affixed in some blow-by-blow comparison chart alongside Sampras, he is more logically a descendent of Agassi. No matter where a ball lands, Federer can attack it. For his opponents, every rally is wrought with tension, and the anticipation of a swift and humbling conclusion to a point.That Federer can volley well and move with uncommon speed and grace merely builds on his foundation. Agassi could make any surface conform to his style, while Federer can impose any style he likes on any surface: baseline dominance at Wimbledon, or rushing the net on clay, as he did in the final of the Rome Masters this year against Nadal in what remains the most splendid tennis match of the season, if not the decade.

Although men’s tennis will lose its most popular star in the next several days, because of Agassi’s spirit and persistence the future of the sport is as bright as it has been in 30 years. On court, the game is fast-paced, athletic, and populated by seemingly impossible feats of balance and displays of geometry. Off court, its stars are increasingly mature and intelligent, as Federer and Nadal so often remind us. Whether the public draw, and the television ratings, will plummet following Agassi’s departure, no one knows. But any decline would have nothing to do with the quality of the game itself. For this, we have Agassi to thank.