Federer Knocked Out At U.S. Open

Roger Federer was unable to set up his first U.S. Open match against Rafael Nadal.

Federer lost in the quarterfinals to Juan Martin del Potro in four sets.

The U.S. Open is the only Grand Slam tournament where Federer and Nadal have never met. Del Potro will face Nadal in the semifinals.

Madison Keys has made it an all-American women's final four at the U.S. Open.

She will face No. 20 CoCo Vandeweghe tonight in the second semifinal, after ninth-seeded Venus Williams faces unseeded Sloane Stephens.

The Americans hadn't had all four semifinalists at the U.S. Open since 1981, when Tracy Austin beat Martina Navratilova for the title.

The U.S. Open is guaranteed its first all-American final since Serena Williams beat Venus in 2002.