Novak Djokovic has won 27 matches in a row at Grand Slam tournaments. If he can make that 28 by beating Rafael Nadal in Sunday's French Open final, Djokovic will earn a fourth consecutive major title, something no man has accomplished since 1969.

Tough to imagine someone so close to such a historic achievement being an underdog, yet that's exactly the case for Djokovic.

Even the 25-year-old Serb says so.

"You can say that he's a favorite, definitely," Djokovic conceded.

Really? Even though Djokovic beat Nadal in each of the past three Grand Slam finals?

Well, yes. Because as good as Djokovic is on all surfaces and in all settings at the moment, no one ever has been as good as Nadal is on the red clay of Roland Garros. Set aside that Nadal owns 10 Grand Slam titles overall, twice as many as Djokovic, and simply consider the 26-year-old Spaniard's superb French Open bona fides.

While Djokovic hopes to complete a 'Novak Slam' - only two other men in the century-plus annals of tennis have been the reigning champion at all four Grand Slam tournaments simultaneously - Nadal seeks his record seventh trophy at the French Open. Only Nadal and Bjorn Borg have won the title six times.

All told, Nadal is 51-1 at his favorite tournament, including 3-0 against Djokovic, who's never before reached the final in Paris.

"He has lost, what, two matches in his career here?" Djokovic asked during a news conference after eliminating 16-time Grand Slam champion Roger Federer in the semifinals.

As reporters began to correct Djokovic's count, he continued: "One? That says enough, I mean, about his quality on this court... I haven't won a set against him in this court. All the facts are on his side."

Nadal's only loss came against Robin Soderling in the fourth round in 2009. And, amazingly, Nadal might be better than ever. He has won every set he's played over the past two weeks, losing a total of only 35 games through six matches, the lowest total for a player getting to the final at any major tournament since Borg's 31 at the 1980 French Open. Nadal has won 71 of 72 service games, saving 18 of 19 break points.

"His position on the court is better. His serve is better in this tournament. And his backhand is so much better," said Toni Nadal, Rafael's uncle and coach. "It's also about his head, knowing when to come forward more, play more aggressive."

Djokovic, it must be said, keeps getting better, too.

It's been more than a year since he lost a Grand Slam match against anyone, anywhere: June 3, 2011, in the French Open semifinals, when Federer snapped Djokovic's 41-0 start to last season.

Since then, Djokovic has gone 7 for 7 on the grass courts at Wimbledon in late June and July, then 7 for 7 on the hard courts at the U.S. Open in late August and September, then 7 for 7 on another type of hard courts at the Australian Open in January, and 6 for 6 so far on the clay courts at the French Open in late May and June.

That sort of consistency and versatility is rather rare.

Only Don Budge in 1938, and Rod Laver in 1962 and 1969, have won four Grand Slam tournaments in succession. Budge and Laver went 4 for 4 within a calendar year each time; Djokovic's feat wouldn't quite equal theirs, therefore. On the other hand, Budge and Laver didn't need to master four different playing surfaces.

Since that last Grand Slam 43 years ago, the closest any man came was when Federer twice compiled 27-match winning streaks at major tournaments and needed to win the French Open final to close the deal. His opponent in those 2006 and 2007 finals? Nadal, of course.

Maybe that's why Federer, asked to weigh in with a prediction for Sunday, replied: "I obviously pick Rafa. I think he's the overwhelming favorite."

Easy to forget, perhaps, given his utter dominance of late, but there was a time when Djokovic was not nearly as strong of body and mind as he is now.

He quit during his second-round match at the 2005 French Open. He stopped after losing the first two sets of his 2006 French Open quarterfinal against Nadal, citing a bad back. An infected blister on a toe was the reason given when Djokovic pulled out of his 2007 Wimbledon semifinal while trailing Nadal again. While losing a match against Federer at the Monte Carlo tournament in 2008, Djokovic stopped again, complaining of dizziness and a sore throat.

But a new dedication to fitness and a gluten-free diet have helped Djokovic. So has a self-belief that he says stems from leading Serbia to the Davis Cup title in December 2010.

"I feel different nowadays. I believe I'm at the peak of my career," Djokovic said. "I'm playing the best tennis of my life in last year and a half."

Now, for Grand Slam history, all he needs to do is win once more.

Won't be easy, though.

"Going to be a difficult match for me," Nadal said. "Hopefully, for him, too."