For the first time in 15 years, four American women are into the quarterfinals of the US Open.

One is a constant: two-time US Open champion Venus Williams, who is back into the last eight for the 11th time. In 2002, the last time there were four or more American women in the quarters, Venus was there, alongside sister Serena, Lindsay Davenport, Jennifer Capriati and Monica Seles.

The remaining trio of Madison Keys, CoCo Vandeweghe and Sloane Stephens, however – none of whom were yet teenagers in 2002 – are all in the last eight of the US Open for the first time.

"I'm not really surprised that anyone got this far, but I think we're all cheering for each other, excited that there's four of us in the quarters," said Keys, who rounded out the lineup Monday night with a 7-6, 1-6, 6-4 match upset of No. 4 seed Elina Svitolina. "I've played on a Fed Cup team with all of them, including Venus. I was at the Olympics with all of them. I think we're all cheering for each other.

"To see Sloane coming back from a long injury, having to have surgery. CoCo is always a force to be reckoned with. I don't think anyone is totally surprised about that. Venus has made two slam finals [this year]."

play video Cognitive Highlight: Sloane Stephens - Quarterfinal

The last time four Americans played in the semifinals at the US Open was 1981, when Martina Navratilova defeated Chris Evert and Tracy Austin defeated Barbara Potter. The last time there was an all-American semifinal at any Slam was in 1985 at Wimbledon, when Martina Navratilova defeated Chris Evert to win the title. 

"Unfortunately, I can only talk about myself, because that's the only person I know what I'm doing, of how hard I've had to work to get here to this point and how much I've had to sacrifice to get here," Vandeweghe said after her 6-4, 7-6 fourth round win over Lucie Safarova on Monday afternoon. "I think it's great to have three, maybe hopefully four tonight, Americans in our American Grand Slam."

Previously in Flushing Meadows, the best result for each Keys and Stephens was a fourth-round showing, while Vandeweghe had not been past the second round in eight previous main-draw attempts.

August 30, 2017 - Venus Williams in action against Oceane Dodin at the 2017 US Open. (USTA/Billie Weiss)
Photo by:  (USTA/Billie Weiss)

"Obviously, I could never say, 'Oh, yeah, when I was coming back, I'm going to make two semifinals, a quarterfinal.' I would have been like, 'You're crazy,'" said Stephens, who is playing in just her fifth tournament after nearly a year on the sidelines due to a foot injury. "I definitely think that I'm playing well. I obviously was upset that I was injured, but in that time I got to do all of the things that I would never have been able to do. I really did miss tennis, but now that I look back, I'm so happy I got to do all that stuff. Now, I'm so happy that I'm back playing and in the quarterfinals of the US Open."

While the rising Americans are breaking new ground at this US Open, Williams is celebrating a milestone at this tournament.

Twenty years ago, in 1997, she made the final in her US Open main draw debut. That breakthrough kicked off a run of six straight years where she at least reached the semifinals in New York, which ended with a runner-up finish in 2002.

"I think during this time ... I didn't think. I just went big all the time," Williams said. "That's fun, too, but over time you have to learn the time to go big and the time not to go big. Obviously [the 1997 final] was a very beautiful moment for me. After that I never looked back, I just went bigger. It was awesome. 

"I think success breeds success. If you win, you learn how to win, and you win more. But I'm firmly a person that lives in the future. I don't know. I'm very focused on the next result. No, I don't focus on any success. I'm looking forward."

To take a page from Williams' playbook, and looking forward for this quartet: the last all-American final here was also in that (star-spangled) banner year of 2002.