NEW YORK >> Serena Williams ended a difficult-for-her Grand Slam season in the best way possible, winning her third consecutive U.S. Open championship and 18th major title overall.

And like each of her matches at Flushing Meadows the past two weeks, the final wasn’t close at all — a 6-3, 6-3 victory over good friend Caroline Wozniacki that lasted only 75 minutes Sunday.

Williams equaled Chris Evert and Martina Navratilova with 18 Grand Slam singles titles, the fourth-most in history. Williams also matched Evert’s total of six championships at the U.S. Open and became the first woman to win three in a row since Evert’s four-title run from 1975-78.

Not only did Williams, ranked and seeded No. 1, win all 14 sets she played in the tournament, she never even dropped more than three games in any of them.

When the final ended, Williams dropped to her back behind the baseline, covering her hands with her face. Her first major trophy also came in New York, in 1999, when she was 17.

“It is a pleasure for me to win my first Grand Slam here and then this No. 18,” Williams said, her voice choking. “So I’m really emotional. I couldn’t ask to do it at a better place.”

Williams earned $4 million, a record in tennis — $3 million for the title, plus a $1 million bonus for having had the best results during the North American summer hard-court circuit. Evert and Navratilova joined her on court during the trophy and check ceremony.

Williams also has won five titles apiece at Wimbledon and the Australian Open, plus two at the French Open. Only three players have more Slams to their credit: Margaret Court with 24, Steffi Graf with 22, and Helen Wills Moody with 19.

Until the U.S. Open, though, Williams had not been at her best on her sport’s biggest stages in 2014. She lost in the fourth round at the Australian Open, the second round at the French Open, and the third round at Wimbledon, where a disoriented Williams also struggled through an odd appearance in doubles that was attributed to a viral illness.

Back at the top of her game, Williams broke Wozniacki’s serve five times and compiled a hard-to-believe 29-4 edge in winners.

“You really deserved it today. You played better than me,” the 24-year-old Wozniacki said. “You’re an unbelievable champion and you’re an inspiration to me, both on and off the court. You’re an unbelievable friend — and you definitely owe drinks later.”

Remarkably, until a cross-court backhand on the run in the final game that Williams applauded, the only winners registered by the 10th-seeded Wozniacki came on a trio of aces.

That was, in part, a result of the Dane’s iffy play in only her second Grand Slam final — she lost to Kim Clijsters at the 2009 U.S. Open — but mainly due to Williams’ relentless pursuit of every ball.

A few weeks shy of her 33rd birthday, making the American the oldest major champion since Navratilova was 33 at Wimbledon in 1990, Williams powered this way and that in her black-and-pink hightops. Wozniacki is the one training for the New York City Marathon, but she was tuckered out by the end.

Wozniacki may as well have been an extra in this Williams highlight reel. Points were directed by Williams, via serves that reached 120 mph (194 kph), forceful returns that backed Wozniacki into a corner when not producing outright winners, unreachable groundstrokes or the occasional volley.

Yes, this was all about Williams. At times, it felt as if Wozniacki were there because, well, someone needed to be on the opposite side of the net.

They’ve been pals for years, and they hung out together in Miami — heading to the beach, watching an NBA playoff game — after both lost early at the French Open in May. Wozniacki says Williams helped her get over the end of her engagement to golf star Rory McIlroy.

“We text almost every day. She’s such a great person, a nice friend,” Williams said, before turning to address Wozniacki.

“I know you’re going to be winning very, very soon, maybe even Australia,” Williams said, referring to the next major tournament, in January, “so I got to go home and get fit again so I can be ready for you there.”

The friendship between Williams and Wozniacki did not matter one bit, of course, while they played with so much at stake as early evening shadows moved across Arthur Ashe Stadium.

As Williams put it beforehand, referring to her older sister, “If I can play Venus, I can play anybody.”

Sure looked that way Sunday.