NEW YORK (AP) For the second time in his career, Novak Djokovic ends a season with three Grand Slam titles. Unlike in 2011, though, he played in all four major finals this year.
His riveting 6-4, 5-7, 6-4, 6-4 victory over Roger Federer in the U.S. Open final Sunday night left so little between his three titles and a perfect Grand Slam season - a loss to Stan Wawrinka in the French Open final.
On the other hand, unlike Serena Williams, whose pursuit of a calendar-year Grand Slam ended in the semifinals at Flushing Meadows, Djokovic did not have to deal with the mounting pressure of heading to the U.S. Open in search of that rarest of achievements in tennis.
Looking ahead to 2016, it's clear that both Djokovic and Williams could resume that Grand Slam quest, with not too many players capable of standing in the way.
''Seems like there are not many guys that can hang with him, don't have the tools or dare to go forward, or they aren't (daring) to serve-and-volley against him, because he's so good on the return. Which he is. He's perfected his game on the hard courts, no doubt about it,'' Federer said. ''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.''
Well, that covers the surfaces used at the Australian Open, French Open, Wimbledon and U.S. Open.
''To say the least, it's very impressive. He's having unbelievable career. I think everybody knows that he knows that, as well,'' Federer said. ''Tonight is another example of that.''
Add up all of Djokovic's major trophies - at least two from everywhere but Paris, where he has yet to triumph - and he's up to 10, tied for seventh in history with Bill Tilden, and trailing only Federer (17), Pete Sampras (14), Rafael Nadal (14), Roy Emerson (12), Bjorn Borg (11) and Rod Laver (11).
''Well, we got to double-digits now,'' Djokovic said, ''and I'm so obviously flattered and honored to be a part of elite group of players, legends of our sport, to manage to win this many Grand Slam trophies in their lives and careers.''
The 28-year-old Serb has been gaining on Federer, thanks in part to beating the 34-year-old Swiss star in three of the past six major finals.
''Clearly, he can win many of them,'' Federer said. ''He already has a ton, so obviously he's got to stay healthy and all that stuff and hungry.''
Here is what else we learned at the 2015 U.S. Open:
FEDERER'S GAME: Thanks in part to his recently developed ''SABR'' - ''Sneak Attack by Roger'' - half-volley return, a healthy back, and a larger racket head that he is fully comfortable with, Federer has played superbly of late. He is 17-2 over his last 19 matches, the only losses coming against Djokovic in the Wimbledon and U.S. Open finals. ''He came close at Wimbledon. He came close this time,'' said Federer's coach, Stefan Edberg. ''You still cannot count him out. If he keeps playing at this level, he'll get another shot.''
NADAL AND MURRAY: Nadal lost in the third round, Andy Murray in the fourth, and while most folks still consider them to be part of the ''Big Four,'' along with No. 1 Djokovic and No. 2 Federer, there will be those who wonder when either will again be lifting a Grand Slam trophy. For Nadal, especially, there are serious questions about whether the pounding his style of play puts on his body has taken an irreversible toll. This was the first season since 2004 that he did not win a major title.
HOW WILL WILLIAMS RESPOND?: Williams' loss to 43rd-ranked Roberta Vinci in the semifinals was as surprising a result - if not THE most surprising result - as tennis has had in any recent times. Vinci played superbly, but Williams, no matter how much she denied it, looked as if the tension and attention brought on by her Grand Slam attempt finally got to her. She turns 34 this month, and 20-something opponents such as Victoria Azarenka, Petra Kvitova and Caroline Wozniacki must be hoping the American will slow down at some point.
RAISE THE ROOF: There's a reason the U.S. Tennis Association was implored for years to put a roof atop Arthur Ashe Stadium: It tends to rain in September in Flushing Meadows. The men's final was delayed for more than three hours, but at least finished Sunday night. Work is scheduled to resume soon on the retractable roof that is supposed to be in place for the 2016 tournament.
Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich