The win marks Novak Djokovic's 10th Grand Slam title of his career.
Novak Djokovic defeated Roger Federer in the 2015 U.S. Open final on Sunday, winning his third Grand Slam title of the year.
After rain delayed the start of the match by more than three hours, Djokovic earned a 6-4, 5-7, 6-4, 6-4 victory at Arthur Ashe Stadium.
The victory marks No. 1 Djokovic's 10th Grand Slam title and second U.S. Open title. He made all four Slam finals this year, only failing to win the French Open.
Djokovic also won three Grand Slams in 2011.
“Winning Grand Slam is very special for any tennis player when you are dreaming of becoming a professional tennis player,” Djokovic said. “When you are kind of finding that inspiration, motivation, these are the tournaments you dream of winning.”
Federer hadn't dropped a set entering the final, but Djokovic broke him twice in the first set. Federer, a five-time U.S. Open champion, had only been broken twice on 81 previous service games this tournament.
Federer recovered and won the second set, which lasted one hour and two minutes. Up 6-5, Federer earned his second break of the match over Djokovic, much to the delight of the crowd, most of which raucously supported the 17-time Grand Slam winner.
“Was it louder than ever?” Federer said. “Maybe. It was unreal.”
Added Djokovic: “I can't sit here and criticize the crowd. On the contrary, I think it's logical to expect that a great player and a champion like Roger has the majority of the support anywhere I play him.”
Djokovic halted Federer's momentum with an early break in the third set, which Djokovic won 6-4. After Djokovic went up two breaks in the fourth, Federer rallied from a 5-2 deficit, but Djokovic held serve at 5-4 to clinch his second U.S. Open title.
Federer, the world No. 2, converted just four of 23 break point opportunities throughout the match.
“I had my chances on my racket,” said Federer, who recorded 54 unforced errors. “I should never [have] been down in the score the way I was. But Novak did a great job of fending them off.”
Federer, 34, hasn't won a Grand Slam event since Wimbledon in 2012. He last won the U.S. Open in 2008.
Djokovic beat Federer in the Wimbledon final earlier this summer.
“It's an ultimate challenge that I can have now winning against Roger back to back finals in Wimbledon and here, U.S. Open,” Djokovic said. “It's tremendous. I'm really, really proud of it.”