Is Novak Djokovic in Rafael Nadal’s head?

So far this year, the answer has been an unequivocal yes.

Djokovic has beaten Nadal in five finals and on three surfaces, including the big stage of the Wimbledon final, during his incredible 2011.

Now, the two best players in the world will tangle for the U.S. Open championship today.

“This year I lost the last five finals against [Djokovic] so this will be the sixth,” Nadal said. “That’s an advantage for him. He’s obviously the favorite for the final.

“I know I have to do something better than the other matches to try and change the situation, and that’s what I’m going to try.”

Nadal joked that he might try to “serve and volley” in the final instead of grinding it out from the baseline. Of course, his bread and butter comes from the baseline, even if John McEnroe calls Nadal one of the best volleyers in the world.

The good news for Nadal is that he will now get a full day’s rest after having played Thursday, Friday and Saturday. The final was pushed to Monday because it rained two days in a row last week.

“Is beautiful have one day off after few days,” Nadal said. “It’s fantastic.”

Nadal had not lost a set through five matches here before showing a chink in his armor in the third against Murray, who is still seeking his first major title.

“He’s playing well,” Murray said of Nadal. “He’s had an incredible year. He hadn’t lost a set in this tournament until tonight, so it would suggest he’s playing pretty well.”

Still, Nadal is now 59-10 in 2011 and half of those losses have come against Djokovic, now an amazing 63-2 on the season.

“I know that I have a game that is good enough to win against him,” Djokovic said after he fended off double-match point against Roger Federer for the second straight year in the semifinals to win in five sets. “I proved that this year in three different surfaces, so I believe that I have a good chance.”

He added: “I need to go on the court believing I can win. But, you know, we’re talking about a player who has won 10 majors already in his career and he’s only 25. He’s defending his title.

“I think last year in 2010 throughout the whole tournament and in the finals I never seen him serve better than that tournament.”

Nadal’s wicked left-handed, topspin forehand comes up high on Federer’s one-handed backhand and makes it difficult for him to handle.

Yet because Djokovic swings with a two-handed backhand, he is able to take that shot higher up and send it back with pace.

“If I play my good shot against his backhand, the forehand with topspin long, normally I will take advantage on the point,” Nadal said. “But I have to do it not one time. I have to do it 1,000 times during the match. That’s what I really have to do, and that’s what I gonna try.”

If Djokovic wins the Open, he will become just the sixth man to capture three majors in one calendar year. (Rod Laver won the Grand Slam in 1969, and Federer won three majors in three different years.)

If, however, Nadal can add the U.S. Open to his French Open title and then finish off the year strong, he could potentially challenge Djokovic for the No. 1 ranking this year.

His 11th major would also tie him with Bjorn Borg and Rod Laver on the all-time list.

“The only way to beat him,” Nadal said of Djokovic, “is believe in the victory, play aggressive and play perfect in every moment.”

Follow Adam Zagoria on Twitter @AdamZagoria.