It’s the solemn duty of every sportswriter to discover—or failing that, to create out of thin air—“turning points” in the history of competitive athletics. This may sound like a laborious task, but we have many tools at our disposal. There is the “changing of the guard.” There is the “end of an era.” There is the “new generation” of "young guns" and "hot shots," or, in the unfortunate case of tennis 10 years ago, “new balls.” Never mind that some of these hot shots and new balls may be only two or three years younger than the last generation; it’s all about finding the new, the different, the improved.

Tennis in particular lends itself to the turning point; the sport’s eras have been easy to designate in recent decades. One player—Sampras, Graf, Federer, Serena—will become the face of the game for a certain period. When that player loses his or her grip on the tour, there may be a brief sorting out process, out of which will rise a new champion for a new era.

There are also obvious broader changes that have transformed the sport and created dividing lines between eras. With each decade, the players have gotten stronger, and so has the equipment. The most dramatic of these transitions happened in the 1980s, when the pros switched from small wooden racquets to larger-headed graphite frames. Watch a clip of the all-wood 1980 Borg-McEnroe Wimbledon final. Then watch a clip of the no-wood 1988 Masters final between Boris Becker and Ivan Lendl. (Were the late-80s and early-90s the most entertaining era in tennis, after all? I smell a topic for investigation during the off-season.) Finally, watch a men’s match from China this weekend. You’ll see that more changed in that first, eight-year interval than in the last 21 years.

But there has been one significant changing of the technological guard during that second span, even if it’s impossible to notice at first glance. It’s in the strings. The crucial moment came at the 1997 French Open, when an unknown 20-year-old Brazilian named Gustavo Kuerten showed up in Paris with polyesther strings made by a Belgian company called Luxilon—previously famous for making bra straps—and won the French Open.

The clip above is from Guga’s semifinal that year against Filip Dewulf. Can we see a “turning point” in the making?

—First we remember the clothes. The bright blue and yellow, like a burst of Technicolor in the middle of a black-and-white film. Also, his ensemble was more original and easier on the eye than Andre Agassi’s ill-begotten forays into loudness earlier in the decade.

—Next we remember the Guga grunt, which would be extended into a long sigh in future years.

—Then we see the face and the long hair, still straight to his shoulders at this point, like he’d just wandered off the beach looking to hitch a ride back to his parents' place. The Parisian crowd embraced Kuerten, and he embraced them back. His free-spirited nature boy style must have appealed to their artistic sense.

—Then there’s the light-on-his-feet movement across the baseline, helped by the most natural of slides. I’d forgotten how open Guga’s stance was on his forehand. Did this contribute to his subsequent hip problems?

—Now we take a second, one second, to acknowledge the guy across the net. Filip Dewulf. Also out of nowhere. But lacking the bold clothes or the stylish game or the je ne sais quoi—it’s hard to recall a funkier serve or forehand.

—OK, back to Guga. There are signs here that he’s doing things that hadn’t been done consistently in the past. Watch the backhand down the line winner from behind the baseline. That had generally been reserved for guys with two-handers. Then watch Kuerten’s forehands and backhands dip as they head for the sidelines. While he doesn’t generate the same kind of heavy spin that Rafael Nadal does today, Guga's strokes are still more reminiscent of 2009 than they are of 1989.

—So is Luxilon the key ingredient? Are we now watching a power polyester game—virtually every pro today uses Lux in some form—as opposed to the finesse-oriented gut game of the 50s, 60s, and 70s? There are conflicting theories on the subject, some of which were addressed in a Time Magazine article in June called, naturally and dully, "The String Theory." (It's available online, but it won't open for me right now.) There’s no proof that polyester does anything to the ball to increase spin, and one researcher maintains that the pros are still adapting to a more fundamental change, the widening of the racquet face in the early 80s.

Still, when I tried a full set of Luxilon, I did generate more spin, both top and slice (but mainly top). I also generated a sore shoulder, so I switched to Lux in the main strings and a durable synthetic in the crosses, a blend that I’ve used for four years. Of course, the extra spin could also be a product of the “dead” feel that polys are famous for, which induces players to swing harder (and get sore arms).

—Whether or not this is an important moment in the evolution of tennis is up for debate. What isn’t debatable is the bittersweet nature of seeing a young, fresh Kuerten dancing across the clay at Roland Garros. Was he a casualty of the modern power game he helped create? Was he a guy with a body built for an earlier era who accidentally started a new, more physical one? Sportswriters can place Kuerten on a tennis time line like any other champion. We can reduce his backhand and his string choice to evolutionary steps in the sport. But why would we want to do that?

This clip shows that, for me at least, the blue-shirted beach bum from Brazil will always exist just a little outside of tennis time, free of its conventions. We identify most of the top players—Rafa, Roger, Steffi, Martina—with a single name. But with Kuerten we only needed two syllables. Whomever coined it, the combination of "goo-goo" with "gaga," of the childlike with the exuberant, was a perfect fit. It let you know you one thing right away: You were probably going to like watching this guy play tennis.

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Have a good weekend. Lots of matches coming up on the Tennis Channel. But if you get a spare moment, say a prayer for the Philadelphia Phillies, too. Thanks.