Djokovic is unbeaten so far in 2011, a 37-0 record that includes seven titles from seven tournaments and victories over Nadal in finals the past two weeks on clay _ the surface used at Roland Garros.

Nadal, for his part, can derive confidence from his success at past French Opens: He is 38-1 with five titles over his career at the year's second Grand Slam tournament.

When play begins in Paris on Sunday, the focus squarely will be on those two men _ No. 1-ranked Nadal of Spain and No. 2-ranked Djokovic of Serbia _ and whether they will meet in the June 5 final.

Roger Federer's only-by-his-high-standards slump is among the other stories of interest. A wide-open women's draw is missing both Williams sisters but features Kim Clijsters' first French Open appearance since 2006, Maria Sharapova's bid to win the only Grand Slam title missing from her resume, and top-ranked Caroline Wozniacki's pursuit of her first major championship.

The main questions, though, concern Djokovic and Nadal.

Can Djokovic win his second consecutive Grand Slam title and break John McEnroe's Open era record for best start to a season, 42-0 in 1984? "He is playing fantastic," Nadal acknowledged.

Can Nadal equal Swedish great Bjorn Borg's record of six French Open championships? "Let us be clear: He is the 'King of Clay,' and he is the best player ever to play on this surface," Djokovic said about Nadal.

Hard to argue with that.                                

Since the start of the 2005 season, Nadal is 193-8 on clay, including an 81-match victory run during one stretch.

At Roland Garros, he's won 113 of 123 sets in his six previous appearances, and his only loss came to two-time French Open runner-up Robin Soderling of Sweden in the fourth round in 2009.

As none other than 16-time Grand Slam champion Federer put it at the start of the European clay-court season: "Look, we all know how good Rafa is on this surface." Indeed, Djokovic is the only player to beat Nadal twice in one season on the slow, red stuff, accomplishing that with straight-set victories in the championship matches in Madrid and Rome this month.

Entering this season, Djokovic was a combined 13-29 against Nadal and Federer, the two players who have finished ahead of him in the rankings the past four years.

But he's 7-0 against them in 2011, losing a total of only three sets in those matches.

Djokovic's 4-0 record against Nadal was compiled entirely in tournament finals, and they only could meet at that stage at the French Open, too. If they do, it would be a rematch of September's U.S. Open final, which Nadal won for his ninth Grand Slam title and third in a row.

Djokovic stopped that streak by winning the Australian Open in January for his second major trophy. Now, thanks to his remarkable start to this season, Djokovic could replace Nadal atop the ATP rankings for the first time. To remain at No. 1, Nadal must win the French Open and have Djokovic lose before the final, according to the ATP World Tour.

Another way to look at it: If Nadal fails to take home the title, Djokovic will become No. 1 _ no matter what he does in Paris.

For so long, it was 2009 French Open champion Federer who owned that top ranking and who was the center of attention at Grand Slam tournaments.

But as he approaches his 30th birthday in August, Federer is no longer the dominant figure that he was. After reaching 23 consecutive major semifinals, he was upset by Soderling in the French Open quarterfinals last year, then lost to Tomas Berdych of the Czech Republic in the Wimbledon quarterfinals.

Those were followed by losses to Djokovic in the semifinals at both the U.S. Open and Australian Open, which means Federer enters this French Open in his longest Grand Slam drought since winning his first major title at Wimbledon in 2003.

"Roger is still playing great. A couple of guys have stepped up, and Novak and Nadal right now are hitting their prime," said Pete Sampras, whose record of 14 career Grand Slam titles was broken by Federer in 2009. "Roger _ he'll find his way." Federer has won at least one Grand Slam title in each of the past eight seasons, tying a record shared by Sampras and Borg. All streaks eventually end.

Djokovic is hoping his will last at least another seven matches, which would be enough to give him his first French Open championship, his third Grand Slam title overall, the No. 1 ranking, and a 44-0 record in 2011, two better than McEnroe managed 27 years ago.

"This is really, potentially, a monumental effort. If he were to win the French, he could almost lock up the (year-end) No. 1 player in the world," McEnroe said.