Petra Kvitova and Venus Williams have played each other five times, and on each occasion they have taken each other to a deciding set. The Czech leads the head-to-head 4-1, and 3-1 on hard courts. Kvitova's victories include their first encounter, which she won 2-6 6-4, 6-3 as a 17-year-old ranked No.129 in the first round of Memphis in 2008, and their most recent match, 5-7, 7-6(2), 7-5 in the third round of Wimbledon 2014 on her way to the title. Williams's sole win came in the second round of Miami in 2012 by a score of 6-4, 4-6, 6-0.
Today's quarterfinal will be Anastasija Sevastova and Sloane Stephens' first career meeting. Sevastova is in the last eight of a Slam for the second time following her quarterfinal run here last year, while this is the third time Stephens has reached this stage following her semifinal run at the Australian Open in 2013 and Wimbledon quarterfinal in the same year.
Venus Williams is 22-16 in the quarterfinal stage of majors, and 8-3 at the US Open. The last time she reached the semifinals in Flushing Meadows was 2010, when she beat Francesca Schiavone in the last eight. 2010 was also the last year in which Williams reached the second week at all four Slams, a feat she has now accomplished five times in her career (1998, 1999, 2002, 2010 and 2017). The only other woman to have achieved it this year is Garbiñe Muguruza.
Petra Kvitova is 5-4 in Slam quarterfinals, but just 0-1 at the US Open. Her sole last eight showing here was in 2015, when she lost to eventual champion Flavia Pennetta.
World No.83 Sloane Stephens is bidding to become the seventh player ranked outside the Top 50 to reach the US Open semifinals. The American would be the joint fourth lowest-ranked player ever in the last four, following Angelique Kerber (No.92 in 2011), Billie Jean King and Kim Clijsters (unranked in 1979 and 2009 respectively) - though No.418 Kaia Kanepi could trump her if she wins her quarterfinal tomorrow.
If Anastasija Sevastova wins today, it would mark the 18th consecutive major to feature a debut semifinalist, a streak stretching back to Kirsten Flipkens' run at Wimbledon 2013.
Petra Kvitova is the only remaining player yet to drop a set in the tournament; each of the other quarterfinalists has lost two sets aside from Anastasija Sevastova, who has ceded just one. Kvitova, Sloane Stephens and Madison Keys are the only quarterfinalists who have played the maximum of two seeds en route to their last eight spots.
One month ago, Sloane Stephens was ranked No.934 following 10 months on the sidelines recovering from foot surgery. During her time off, she kept in touch with the sport through commentary gigs - which were a great help to her comeback, reports Stanley Kay for Sports Illustrated.
The quarterfinal between Petra Kvitova and Venus Williams won't just pit the two most accomplished players remaining against each other, but two of the most inspiring comebacks. Sandra Harwitt reports on the adversity each has faced for USA Today.
Rounding out a bottom half defined by comeback stories is Anastasija Sevastova, who retired for two years following chronic injuries and illness in 2013. Catch up with the Latvian with our WTA Insider interview.
Relive Madison Keys' epic late-night victory over Elina Svitolina from yesterday.