Serena Williams beats Caroline Wozniacki to win her sixth US Open

Serena Williams has clinched a record-equalling sixth US Open title and an 18th major championship after beating Caroline Wozniacki in the women's singles final.

Williams won 6-3, 6-3 in an hour and 15 minutes to go fourth on the all-time grand slam singles titles list for women, level with Chris Evert and Martina Navratilova on 18 majors.

Williams is also level with Evert for most US Open titles with six triumphs, having now won three in a row at Flushing Meadows.

She had failed to progress beyond the last 16 of 2014's first three majors, but capped off her US Open triumph without dropping a set throughout the tournament.

"It is a pleasure for me to win my first grand slam [tournament of 2014] here and number 18," an emotional Williams said.

"I couldn't ask to do it at a better place.

"Congratulations to Caroline, she knows the struggles I have had. She's a real nice person, a great friend. We text each other all the time. You will win a grand slam title soon."

World number one Williams' win netted her the biggest cheque in tennis history - $US4 million ($A4.33 million), which include, including a $US1 million bonus for also winning the US Open summer series.

"I have been trying to reach [the final] for so long, since last year. I didn't really think I would get there. I just felt so good," Williams said.

"I definitely did not think I was going to win a slam this year.

"To win the US Open, that was my dream. Every time I win here it's just a really incredible, special moment for me.

"I'm just a simple individual who just wants to win titles and wants to play tennis.

"The reason I play is to sit at the end of the day and hold the trophy or stand and hold the trophy. For me, that's my joy."

Williams broke Wozniacki four times in a messy first set which saw both players struggle to dominate with the serve, taking out the first 6-3 in 40 minutes.

After hitting 15 winners to Wozniacki's one in the first set, the match looked to be racing to a rapid conclusion.

Williams was moving more freely in the second set, but benefitted from a lucky net-cord bounce to cap off a 20-shot rally, giving her break point in the second game, which she converted for a 2-0 lead.

Excellent court coverage and approach play saw Williams hold serve for 3-1, before both players exchanged service games for the American to lead 4-3.

Wozniacki threatened to break Williams' serve in the eighth, but she responded with an authoritative forehand winner to go 5-3 up in the second.

Chasing tennis immortality, Williams used her surging momentum to break Wozniacki to clinch a deserved win.

She finished with 29 winners to Wozniacki's four, watching as the Dane hit a backhand long before dropping to the floor and covering her face with her hands in elation.

Wozniacki's wait for a major title continues, with the former world number one again finishing runner up in New York, matching her 2009 US Open effort.

"Serena, you deserve it. You played better than me today and you deserve to be the champion," Wozniacki said.

"You are an inspiration on the court and off it. You're an unbelievable champion and a great friend. The drinks are on you tonight.

"When she's on her game it's not fun to play her. She's so strong. She has a good serve and she puts pressure on you straight away.

"When she needs to she can pull out that big serve. She has the power. She can push us back on the court and take the initiative.

"She definitely has the experience now, as well. I think that makes it even harder, because maybe back in the day she might have made not the right choices.

"Now she knows what she needs to do out there, and it makes it even harder to beat her."