Madison Keys beat Kaia Kanepi in straight sets to set up an all-American line-up in the semi-finals of the US Open.

Venus Williams and Sloane Stephens had already made it through to the last four, where they will play each other, before Keys and Coco Vandeweghe also booked their spots.

Keys saw off her opponent with ease, going through 6-3 6-3, while Vandeweghe, seeded 20th, earlier beat Czech top seed Karolina Pliskova 7-6 (7-4) 6-3.

It is the first time since 1981 that four American women have made the semi-finals in New York, and Keys could not hide her delight afterwards.

"This means the world to me," said Keys. "I'm just so happy to be here. We're going to have four American women playing tomorrow, and that's pretty awesome."

"I was real nervous today. The car ride over I was definitely feeling it, but once I got out here I felt really good."