Novak Djokovic could not find his keys.

Alone in a parking lot outside Arthur Ashe Stadium at about 2 a.m. Monday, a handful of hours after beating Roger Federer in the U.S. Open final for his third major title of 2015 and 10th overall, there stood Djokovic, unable to unlock the car he'd been using to drive himself between the tournament site in Queens and the hotel near Central Park where he stayed with his wife and their 10-month-old son the past two weeks.

Turned out, he said, a member of his entourage accidentally grabbed the keys while gathering Djokovic's bags. So Djokovic reluctantly accepted a ride from a U.S. Open courtesy car, which is how most players get around. It's just that this 28-year-old from Serbia prefers to be in the driver's seat, an apt metaphor for his Grand Slam status these days.

"It gives me a little bit of time for myself, to relax. Listening to music, going through my thoughts. I love driving here, because I don't get a lot of chances to do that throughout the year," Djokovic said Monday.

"I actually was very much looking forward to that champion's drive from the tennis court to the hotel," he added with a laugh, "but it wasn't meant to be, I guess."

Djokovic's voice was scratchy and he coughed a few times during an interview with The Associated Press as he made the rounds on the morning TV talk-show circuit, where hosts fawned over his newest silver trophy.

He is gaining on Federer's record of 17 Slam championships. Djokovic won their past three major final meetings; reverse those results, and Federer's lead would be 20-7.

As it is, Djokovic stands tied for the seventh-most major titles in history; Pete Sampras (14), Rafael Nadal (14), Roy Emerson (12), Bjorn Borg (11) and Rod Laver (11) are the only others ahead of him.

"I would lie if I said that I am not aiming to maybe at least match or surpass some guys like Pete or Nadal, even if Nadal is still playing, obviously, so he still has a chance to increase his number," said Djokovic, who clinched the year-end No. 1 ranking for the fourth time. "I want to keep on going, and hopefully have longevity in my career, because if I continue doing what I'm doing ... I have a fair chance to win a couple more."

After watching Djokovic beat No. 2 Federer 6-4, 5-7, 6-4, 6-4 on Sunday night, Mats Wilander, who won three major tournaments in 1988, made the point that Djokovic can succeed on any surface, against any style of play and against any specific opponent.

Federer offered a similar assessment.

"He's just really consistent. Seems like there are not many guys that can hang with him. ... He's perfected his game on the hard courts, no doubt about it. He was always a great clay-court player. And because he moves as well as he does, he's solid and consistent now on the grass," Federer said. "To say the least, it's very impressive."

Djokovic joined Federer (2004, 2006, 2007) and Laver (who won a true Grand Slam in 1969) as the only men in the Open era, which dates to 1968, to reach all four major finals in a year.

Djokovic went 27-1 at Grand Slam tournaments this season, the lone loss against Stan Wawrinka in the French Open final.

"I really feel like everything happens for a reason," Djokovic said. "If I won that match, God knows if I would be able to win Wimbledon. Maybe I would be satisfied."

He paid attention to what Serena Williams went through, arriving at the U.S. Open in pursuit of a calendar-year Grand Slam before falling two victories shy.

Djokovic, yet to win the French Open, has never made it halfway to the Grand Slam.

"There was immense pressure on her ... and you could sense that in her semifinal match," Djokovic said. "But that proves that she is also only human and that it can happen, even to her, one of the most dominant athletes in the history of sports."

So he's thought about what it might feel like to deal with that sort of attention?

"I would definitely not mind," Djokovic said, chuckling. "I hope we'll be having a different discussion next year, before the U.S. Open, with having three (majors) in the pocket. But you need to be humble. You need to be able to take one step at a time, then see where it takes you."

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Howard Fendrich covers tennis for The Associated Press. Reach him at hfendrich@ap.org or via Twitter at http://twitter.com/HowardFendrich