What's next for Novak Djokovic?

It's Rafael Nadal's world at the moment, and rightfully so: At the U.S. Open, Nadal became the first man since Rod Laver to win three consecutive Grand Slams on three very different surfaces. Still, it was hardly a surprise that the No. 1 player in the world would win a tournament. What was surprising, and more intriguing for the immediate future of the men's game, was the performance of the man whom Nadal beat in the Open final, Novak Djokovic.

Here was a guy whom no one had touted as a contender -- that honor went to Andy Murray, if you can remember that far back. Here was a guy who appeared to be toast right off the bat, when he went down two sets to one and a break in the fourth to his countryman, Viktor Troicki, in the first round. And yet Djokovic survived to pull off the biggest upset of the tournament, beating Roger Federer in the semis.

Although Djokovic has remained in the top five of the ATP rankings during the past two years, this win marked the first time that we'd glimpsed him in world-beating form at a major since the 2008 Australian Open, where he also beat Federer in the semis on his way to the title. In those days, it appeared that we were seeing a future No. 1, but it was Nadal who grabbed that mantle and left Djokovic to wobble on the game's second rung.

In his postfinal news conference, Djokovic was asked whether he felt he'd "reinvented himself" at this Open. He took the long view, saying that he felt he'd steadily been improving since Wimbledon and that he was happy with this result. It wasn't quite the hungry, enthusiastic answer I expected, but then again, he'd just walked off the court after losing to Nadal in four arduous sets, and he was staring at an immediate trip to Serbia to play Davis Cup on clay -- an event that, if anything, will be even more intense and draining than his experience at the Open.

Once he recovers from that, what will the Open -- the stunning win and the gutsy defeat -- mean for Djokovic's future? On the upside, after losing to Federer in the same round at Flushing the past two years, Djokovic proved that he can still play with the very best and beat them when they're on their games. Federer had his struggles in that match, especially with his serve, but Djokovic was the better player throughout. He had the answers to some of Federer's best stuff in the fifth and was striking the ball well enough to go for broke even when he got down match point. We weren't wrong back in '08: Djokovic has a No. 1 player's game inside him.

But he's still not quite convinced. Although Djokovic played valiantly against Nadal and hit hundreds of jaw-dropping shots along the way, he acted as though the cause ultimately would be a lost one. Take one example. In the third and decisive set, Djokovic swatted away nearly 20 break points and forced Nadal to serve for it at 5-4. At 30-30 in that game, Nadal hit an ace. Djokovic, rather than keeping his focus, threw his hands in the air and looked toward his box as if to say, "This guy is just too good!" The set hadn't even ended yet, but Djokovic was preparing his concession speech.

It's odd. The semis of the Open showed that Djokovic has the game to start winning Slams. The final showed that he doesn't believe it himself. The problem is, you can't have one without the other.