Madison Keys' head-to-head record against Dominika Cibulkova makes encouraging reading for the American. She has won all four of their previous meetings, all of which have been played on hard courts, dropping only one set.
Cibulkova is aiming for a first US Open quarterfinal since 2010 - the only previous occasion the 29-year-old has made it to the last eight in New York.
The American, meanwhile, will be one of just two players to have reached the quarterfinals or better at three of the four Grand Slams in 2018 if she wins.
Since winning the US Open in 2006, Maria Sharapova has reached the quarterfinals only once, in 2012.
Sharapova, the No.22 seed, has a perfect 22-0 night match record on Arthur Ashe.
Carla Suárez Navarro has only beaten Sharapova once in five previous career meetings. Their last match was in Rome 2015, when the Russian came from a set down to win.
In the battle of the 20-year-olds, Naomi Osaka and Aryna Sabalenka are both aiming to reach a Grand Slam quarterfinal for the first time. Osaka lost in the fourth round of the Australian Open earlier this year, while this is already the Belarusian's best major run.
It is the first time Sabalenka and Osaka have faced off as professionals.
Osaka has won a staggering 22-straight games entering Monday's match.
Lesia Tsurenko and Marketa Vondrousova are seeking to reach the last eight of a major for the first time. This is the Czech's first time into the second week of a Grand Slam, while Tsurenko lost at this stage in the 2016 US Open and in the French Open in June.
Vondrousova, the WTA World No.103, is the last remaining teenage in the draw.
Cloudy with spells of sunshine, improving as the day goes on. Maximum temperature: 32C/90F.
Steve Tignor of tennis.com was left impressed by Serena Williams' powerful victory over Kaia Kanepi on Sunday.
Dominika Cibulkova's prospects of going deep into the next week are examined by Tennis World USA's Gail Moorman.
Do taller players have an advantage at the elite level of tennis? The New York Times' Stuart Miller has taken a look.
With seeds falling at every turn, ESPN's D'Arcy Maine says that Maria Sharapova is looking increasingly dangerous.
Naomi Osaka has revealed what she hopes will become the breakfast of champions in New York and admits she'll get "nervous" if she changes now.
ORDER OF PLAY
Check out all of Day 8's scheduled women's matches on the WTA website here.