Novak Djokovic's popularity is such that even the Americans are beginning to love him Go back to the previous generation of giants and Pete Sampras had the unstoppable serve, Andre Agassi the immovable return. And Djokovic? The phrase you often hear is that he doesn't have any weaknesses, which seems an oddly negative way of characterising the best player in the world. But then how else to do it? Justin Gimelstob, the Tennis Channel analyst, says that Djokovic is a hard player to commentate on because there is such subtlety to his game. "Speak to Mardy Fish," Gimelstob said, "and he will tell you that Novak never gives you the same ball to hit twice. You can't get into a rhythm against him, because he is the best guy on the tour at changing the direction of the ball. Most players have certain patterns that they keep to. Think of Nadal camping out on one side of the baseline and using his forehand to dominate. But Novak can go from crosscourt to down-the-line and back again as he pleases. He always takes the ball early and he can put it anywhere. Watch Djokovic playing a night match, dressed all in black, and there is something spider-like about him. He scuttles from side to side with unnerving swiftness, tangling his opponent in a carefully laid web of threads. No stroke is wasted, and no movement either. In a sport that has become almost as attritional as squash, Djokovic is constantly shaving off the margins so that the other guy has to work that bit harder. Are there times when he can seem a little robotic? Perhaps, because he is essentially a grinder. After one of Djokovic's matches, you come away wondering at his intensity, his relentlessness, his will to win. But if you get goose-pimples, they come because of the drama of the narrative, not the beauty of his game. Djokovic will never quite have the "wow" factor of his two chief rivals. Even in a one-sided encounter, a balletic Federer backhand can make you gasp, as may the magnificent violence of Nadal's swooping, swiping forehand. But this is not to denigrate him, for Djokovic has taken the physics of the sport - as they have relentlessly evolved in the current era of slow courts, heavy balls and co-polymer strings - and bent them to his will. Perhaps that's the best way of describing him: not just as a student of the game, but a scientist. Watching from the stands, we can't always see what he is doing - at least, not without Hawk-Eye analysis to highlight those incremental advantages that he feeds off - but we can see that it works. Djokovic's appearance on 60 Minutes - a show that normally concentrates on American stories - proved that he transcends nationality. At the rate he is going, he could yet transcend his sport as well.