Martina Navratilova reckons Serena Williams can go on and match Steffi Graf's Open era record of 22 Grand Slam singles titles.

Williams' 6-3, 6-3 victory over Caroline Wozniacki in the US Open Final on Sunday took her level with Navratilova and Chris Evert on 18.

The figure had been a big target for the American and she admitted it had weighed on her mind as she suffered early exits at the Australian Open, French Open and Wimbledon.

Navratilova and Evert joined Williams on court at Flushing Meadows to present her with a commemorative Tiffany bracelet marking the occasion.

"We all thought it was a matter of when, not if, after she won here last year," said Navratilova.

"It took her the full year, but I think now she doesn't have to talk about it, she doesn't have to think about it and she can just think about 22. That's what she's gunning for next.

"If anyone can get there she can. She's pretty young in tennis terms in that she hasn't played as many matches as I had at this stage of my life.

"Same with Chris or Roger Federer. We had hundreds more matches under our belts. She's pretty young and fresh, and if she stays motivated and healthy, the sky's the limit."

Williams turns 33 later this month and only Navratilova has won a women's slam singles title at an older age in the Open era.

But Williams is unquestionably the No.1 player in the world and shows no sign of slowing up yet.

Navratilova was happy to be joined in the record books, and said: "She plays such amazing tennis.

"She didn't lose more than three games in a set. That's total domination, that's outstanding, no matter what slam it is. She's cemented her No.1 ranking."

Meanwhile, the men's world No.1 Novak Djokovic will skip Serbia's Davis Cup play-off clash against India next weekend, citing "fatigue" following a gruelling year.

Djokovic has been out of sorts since winning his seventh Grand Slam title at Wimbledon in July and suffered a shock defeat in the semi-finals of the US Open to Kei Nishikori over the weekend.