Switzerland's Roger Federer celebrates his victory over France's Richard Gasquet in their quarterfinals match at the US Open Championships tennis tournament in New York September 9, 2015. [Photo/Agencies]

NEW YORK - With rain causing the final women's quarterfinal match to run later than expected Wednesday, the USTA moved the men's quarterfinal match between No 5 Stan Wawrinka and No 15 Kevin Anderson from Arthur Ashe Stadium to Louis Armstrong Stadium. That meant that the two men's quarterfinals would play out almost simultaneously.

When Wawrinka served the first ball, empty seats were few and far between. By the time he closed out the 6-4, 6-4, 6-0 win, the stadium was less than a third full. Everyone had rushed to see the end of Roger Federer's sprint past No 12 Richard Gasquet. Federer prevailed, 6-6, 6-3, 6-1, in less than 90 minutes.

On Armstrong, Anderson double faulted to give Wawrinka the first break of the match at 3-all in the first set. Wawrinka soon fought off a break point opportunity to lead 5-3. Techno beats poured into the stadium as Federer and Gasquet prepared to take the court next door. If that was the music Federer chose to get pumped, it didn't work for his countryman. Wawrinka squandered a break/set-point opportunity.

Playing in his first Grand Slam quarterfinal, Anderson stuck with the two-time Grand Slam champion through the first two sets. It came as no surprise, as the South African had beaten Wawrinka in their last four meetings. The second set stayed on serve through eight games.

That's about the time the cheers from Ashe started to drown out those on Armstrong. At least a third of seats emptied, too, as fans headed over to see the five-time US Open champion in action. Federer led 5-2 just 20 minutes into his match.

The fans who left missed seeing Wawrinka slice a forehand past Anderson to break at 4-4. Serving for the two-set lead, Wawrinka didn't blink. And at that point, the rest of those holding Ashe tickets departed.

Wawrinka must have wanted to get out, too – he quickly bageled Anderson in the sixth set to advance to the semi-final. Moments later, Federer took a two set lead over Gasquet. He'd be done before the clock struck 9pm. The 34-year-old has yet to drop a set in this tournament.

"I think I played a very good match, I felt the ball great from the return," Federer said on court after the match. "My serve worked very well... I was able to stay aggressive and enjoy myself out there, so it was a great match."