IT'S A CHESS MATCH...

Novak Djokovic and Rafael Nadal play in the finals of Roland Garros on Sunday in a match guaranteed to make history. A Djokovic win would be his fourth straight major title. While technically not a Grand Slam (which must occur in the same calendar year), it would nonetheless be an astonishing accomplishment. For Nadal, a victory on Sunday would give him a record seventh French Open title, eclipsing Bjorn Borg, and further cementing his reputation as the best clay-court player ever.

The two men have played in the last three Grand Slam finals, with Djokovic winning in four sets at Wimbledon and the U.S. Open last year. Djokovic defeated Nadal in six straight finals in 2011, on three different surfaces, and the normally imperturbable Nadal looked frustrated at being unable to solve the mystery of Djokovic’s game.

But in their marathon Australian Open final in January, Nadal came within a few points of toppling Djokovic, narrowly losing in five sets. Nadal drew confidence from the close loss, however, and has won their last two matches, in the finals at Monte Carlo and Rome.

Before last year, Nadal dominated the rivalry with Djokovic. He knew that Djokovic had three weaknesses: his serve, which had developed an awkward hitch that led to frequent double faults; his fitness, which was suspect; and his mental game, which led to some dramatic meltdowns in major tournaments. Djokovic’s upset of Roger Federer in the semifinals of the 2010 U.S. Open, in which he saved two match points with daring, aggressive play, signaled a possible breakthrough for Djokovic. Although he lost to Nadal in four sets in the final, Djokovic seemed to grow in confidence. His stirring, emotional play in leading Serbia to the Davis Cup infused him with a buoyant self-belief that he carried into 2011.

How did Djokovic solve the Nadal Problem? How did he turn their rivalry around? He began by returning to his old service motion. After weeks of work, the smooth delivery returned, and Djokovic began to get more free points on his serve. Next, he improved his fitness, getting leaner and improving his strength, speed, and stamina. And he grew more positive and focused on court.

Djokovic dominated Nadal in 2011 by exploiting Nadal’s weaker side — his backhand — and controlling court position to take time away from Nadal. Because Djokovic’s ground game is so balanced, he can transform a point with either a forehand or a backhand. By contrast, Nadal is a forehand-dominant player.

This is a major difference between the two: Djokovic can rip a winner off both sides, while Nadal can dominate with only his forehand. Last year Nadal’s backhand was almost always hit cross court. He seemed to lack faith in his ability to rip a backhand up the line. This made Nadal predictable.

But in the chess match that is their rivalry, Nadal has addressed the weakness of his backhand. He has expanded his repertoire of shots on the backhand side, with a noticeably improved backhand down the line, a heavier, more penetrating slice, and an accurate topspin angle that he places just past the service line to run his opponent wide of the sideline. All of these shots are designed to increase the chances that he can play a forehand, which has become the most lethal ground stroke in men’s tennis.

Another area where Nadal can fall into predictability is his serve placement. Look for him to use more body serves and serves to the forehand to keep Djokovic from getting dialed in with his formidable return of serve. In their Australian Open final, Djokovic kept Nadal under sustained pressure with his consistently deep returns.

For Djokovic, a key to the match will be his ability to win the battle of court positioning. If he can impose his game on Nadal, taking the ball early and pushing Rafa off the baseline with his penetrating ground strokes, then he will force Nadal to cover a lot of ground. Look for Djokovic to go wide to Nadal’s forehand, which will expose the Nadal backhand. Too, Nadal hits way fewer forehand winners when pulled wide than when he gets to run around his backhand and use his favorite winner, the inside-out forehand.

Both men are physically fit, and as we learned in their nearly six-hour contest in Melbourne, they are prepared to suffer. It will be fascinating to watch this match unfold, to see which player can will himself to an historic victory on the slow red clay of Paris.