The ultimate match-up

A dreary weekend forecast calls for a 65 percent chance of thundershowers on Saturday and a 75 percent chance for the same on Sunday for the men's final between top-ranked Novak Djokovic and second-ranked Roger Federer.

Rain had forced the men's final to be delayed until Monday from 2008 through 2012, pushing the US Open to construct the new roof, the superstructure framework for which stands around Ashe this year.

Federer hopes to ride a wave of emotion as he targets a sixth US Open title and 18th major Sunday in a "straight shootout" against world number one Djokovic.

Federer, 34, is bidding to become the oldest champion in New York since 35-year-old Australian Ken Rosewall in 1970.

Federer also has the crowd on his side as he pursues his first Grand Slam title since Wimbledon in 2012.

"I definitely think if there would be more on my side that will give me a lift and extra energy and momentum possibly. That could swing the match a little bit," said Federer, aware that despite his status as world number one, Djokovic often struggles to command a crowd's respect.

“But other than that, obviously Novak is a great player. Both of us have played in all tough conditions, and you've got to play well to beat him. There is no question about that."

There could be spiky sub-plots. Djokovic has been almost dismissive of Federer's new chip-and-charge off a second serve.

"I haven't considered doing that. It's an exciting shot for him. For the player opposite side of the net, not so much. So I have nothing else to say about that," said the Serb on Friday.

Federer says he knows what to expect from Djokovic.

"With Novak it's been more straightforward. That's what I like about the rivalry. I feel like he doesn't need to adjust his game as much," said the Swiss.

"I think it's just a straight shootout, and I think that's the cool thing about our rivalry.

“It's very athletic. We both can handle each other -- whatever we present to one another, and I think our matches are very even.”

Had it not been for Wawrinka defeating Djokovic and claiming the French Open title, the Serb could have been pondering history on Sunday with a calendar Grand Slam.

"We we all know how consistent Roger is and how good he is in the latter stages of a Grand Slams and any other big tournament," said Djokovic, a nine-time major winner.

"He's always going to perform on a high level. Rarely he drops his level. He always makes you play your best.”