NEW YORK (AP) — It will be Sloane Stephens versus Madison Keys in Saturday's U.S. Open women's final.

The unseeded Stephens earned a spot in her first Grand Slam final by outlasting No. 9 Venus Williams, 1-6, 6-0, 7-5. Stephens quickly went up a service break in the third set, but she eventually trailed 5-4 and was two points from defeat before taking the last three games. The rally ended Williams' quest to reach the final for the first time in 15 years.

Stephens is just the fourth unseeded player to reach the U.S. Open women's final in the 49 years of the Open era, and the first since Roberta Vinci in 2015.

The 15th-seeded Keys rolled to a 6-1, 6-2 win over No. 20 Coco Vandeweghe to reach her first Grand Slam final.

Keys won 19 of the first 22 points and raced to a 5-0 lead in an opening set that lasted just 23 minutes. She continued to dominate despite an upper right leg injury that caused her to call the trainer to be taped midway through the second set.

The men's semifinals are Friday.