For the first time since 1985, four American women have reached the semifinal of a tennis Grand Slam event. It's the first time it has happened at the US Open since 1981.

Venus Williams, Sloane Stephens, CoCo Vandeweghe and Madison Keys are the sixth quartet of American women to reach the semifinals at a major. It marks Williams' 23rd Grand Slam semifinal appearance; the other three have combined for six.

Williams is the lone remaining major champion among the semifinalists. She’s looking to reach her third major final of the season, after doing so at the Australian Open and Wimbledon. She'll also be attempting to end the longest drought between Grand Slam titles (36 majors) and become the oldest woman to win a major in the Open era.

Stephens, Vandeweghe and Keys are all seeking their first major final appearance. All three have a chance to become the fourth American woman in the Open era to win her first major title on home soil, joining Tracy Austin, Lindsay Davenport and Serena Williams.

Ranked No. 83 in the world, Stephens would be among the lowest-ranked women to reach the US Open final since the rankings were introduced in 1975.

When Vandeweghe and Keys square off, it will mark the first All-American Grand Slam semifinal that did not feature either of the Williams sisters since the 2001 Australian Open. This is their third career meeting, all of which have come within the past five weeks.