Nadal is still the odds-on favorite to win the French Open, but the odds on a Djokovic win are getting better after he defeated the king of clay in Rome.
Djokovic is clearly the hottest player on the ATP tour, with a 39-0 winning streak going back to his Davis Cup victory last December. This streak doesn't include his wins at the Hopman Cup this January, where he remained unbeaten.
Djokovic always had the game, and now he seems to have found the fitness, the consistency and mental fortitude which were the hallmarks of Federer and Nadal at their peaks.
Djokovic has already won the first Grand slam title of the year and four Masters titles as well as two smaller titles. He has beaten Federer three times, Nadal four times, and Andy Murray twice along the way.
Almost certainly on his way to seizing the No. 1 ranking, Djokovic is heavily favored to end the year at the top of the rankings.
Although Djokovic has a 11-16 head-to-head record against Nadal, he is swiftly moving to reverse the trend.
Djokovic has beaten Nadal at Indian Wells and again at Miami.
This was followed by back to back victories on the clay in Madrid and at the Rome Masters, where he again took out Nadal in the finals.
So, can we write off Nadal's chances at winning the French Open?
Not just yet. Nadal still has some factors in his favor:
1. Nadal has already won five times at Roland Garros. Robin Soderling is the only man who has won three sets against him since 2005 at the venue.
We know that confidence and belief are two of the most important factors for a champion.
If Nadal can focus on his winning record at the French Open and blot out his recent losses to Djokovic, he has a good chance of emerging the winner.
2. Nadal is a master of the five-set format.
Can Djokovic beat Nadal in a five-set match after a grueling two weeks of playing on clay?
3. Nadal is practically invincible on clay against anyone not named Djokovic.
So almost certainly, Nadal will be in the final.
But will Djokovic?
Djokovic has obviously fashioned his game to beat Nadal and Federer, but he has shown vulnerability against some other players on clay. Djokovic struggled against Ferrer, Bellucci and Murray, although he did manage to pull out a win each time.
Still, it's conceivable that he could lose before reaching the final.
4. One can never discount the role of the draw in determining the winner.
Should Djokovic end up with Bellucci, Ferrer or Murray on his side, the chances of him losing before the final go up. Even if he makes it through, he could be too exhausted to withstand five sets against Nadal.
5. Nadal has dominated this surface in a way tennis has never seen before. Unofficially crowned as the greatest clay-courter of all time by many commentators, Nadal has an unbelievable 220-18 win/loss career record in clay-court matches. He has 31 clay-court titles, surpassing the legendary Bjorn Borg. Even more impressive, he's achieved all this before his 25th birthday.
Are mental fortitude, consistency and fitness the only things that prevented Djokovic from beating Nadal on clay in the past? Or is Nadal simply invincible on this surface, with the power to make even Roger Federer struggle on clay?
6. Nadal takes his losses like a champion. He learns from them and improves. Nadal lost to Federer in two Wimbledon finals, then beat him in the next.
Nadal may have figured out how to beat Djokovic.
At Wimbledon, Nadal had two years to learn from his mistakes, but in this case he has had only a few weeks.
However, Djokovic isn't a 20-year-old who has suddenly emerged on the scene. He has been around for some time, and is nearly 24 years old. Because of their familiarity, Nadal already knows Djokovic's game, and may just need to tweak a few aspects of his strategy to regain the edge.
Nadal is almost 25, and although he still has several years of his prime ahead of him, he may already be on the wrong side of the peak many players reach in their mid-20's.
With all these factors in mind, it's extremely tough to predict a winner.
The big difference at the Roland Garros this year is that for the first time since 2006, Nadal is not considered a shoo-in for the title.
Nadal is still the bookies' favorite, but Djokovic is the season's hottest flavor and is quickly gaining support.
Andy Murray is the dark horse. Should he find the motivation, he can easily challenge the top-two for any of the slam titles.
Exciting times are ahead for tennis fans.
No one knows who will win the Roland Garros this year, but one thing is certain.
No matter who takes home the trophy, tennis will be a winner.