A general view of the retractable roof superstructure over Arthur...

A general view of the retractable roof superstructure over Arthur Ashe Stadium at USTA Billie Jean King National Tennis Center in Flushing on Wednesday, Aug. 12, 2015. Credit: Steven Ryan

The roof over Arthur Ashe Stadium isn't complete, so rain can still impact the U.S. Open.

But the superstructure that is in place, along with temporary covers on the west and south sides of the stadium, will have a positive impact on the nature of the playing conditions.

"I've practiced a couple of times on the center court and the roof construction is pretty impressive," said Novak Djokovic. "That has protected the court from the wind, so we have less of the swirly conditions on the court, which does help. In the past, I played many matches where it was hard to control the ball on the court because of the swirly conditions. It's now protected, and it looks impressive, so I can't wait to see the roof next year."

Andy Murray thinks that the shade the superstructure provides will be important during hot times at Flushing Meadows. "Three o'clock onward, it's in the shade," he said. "From 11 o'clock [the start time], there is basically a shadow on one side, which is different from usual. It's not a bad thing. Normally when you are playing a 1 o'clock or 11 o'clock, there's a lot of heat and there's no shade at all on that court, so now there will be a lot of shade, which is not a bad thing because it's supposed to be very hot next week."

Djokovic going for third

If it hadn't been for a magnificently played match by Stan Wawrinka, Djokovic would be going for the same thing Serena Williams is chasing at the Open, a calendar year Grand Slam. Serena is 21-0 in the Slams this year; Djokovic is 20-1 with wins at the Australian and Wimbledon and a loss to Wawrinka at the French Open.

Djokovic has won three Slams in a year once before, in 2011 when he captured his only U.S. Open title. So is it still possible to dream about the Grand Slam of Grand Slams?

"I sincerely hope from your mouth to God's ears," Djokovic said. "It's the only thing I can say. I've been close and that gives me enough reason to believe that I can achieve that. There is no secret, I am trying to win every Grand Slam that I play in. I set myself up for high standards because of the results I've had the past few years. I'm an ambitious guy. I can't predict yes or no, but I can definitely tell you I will do my best."

A qualifying Slam

Elias Ymer of Sweden has achieved something that only one other player has ever done: He earned a spot in the main draw of all four majors by making it through qualifiers. Frank Dancevic did it in 2011. What makes it more impressive is that the 19-year-old of Ethiopian descent had never played in a Slam qualifier before this season. Ymer plays Diego Schwartzman Monday.

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