Madison Keys has made it an all-American women's final four at the U.S. Open.
The No. 15 seed beat Kaia Kanepi 6-3, 6-3 to reach the semifinals of a Grand Slam tournament for the second time.
She will face No. 20 CoCo Vandeweghe on Thursday night 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. Chris Evert and Barbara Potter also made the semifinals.
The last time it happened at any Grand Slam tournament was at Wimbledon in 1985, with Navratilova and Evert joined by Zina Garrison and Kathy Rinaldi.
The U.S. Open is guaranteed its first all-American final since Serena Williams beat Venus in 2002.