Anastasija Sevastova has done well to reach the semi-finals but faces possibly her toughest opponent of the tournament yet. Serena Williams is seeded 17th, just two places above Sevastova, but the Latvian is dwarfed in terms of technique and experience. Williams is hours from winning her first grand slam tournament since her return from giving birth to her first child. Sevastova herself is enjoying a comeback of her own after retiring in 2013 due to injury.
Anastasija Sevastova, left, shakes hands with Sloane Stephens after her victory
Image credit: PA Sport
POTENTIAL UPSET OF THE DAY
M. Keys (USA)  v N. Osaka (JPN) 
Madison Keys will enjoy the home support from the US crowd, and the 23-year-old is the second youngest player of the four left in the tournament. Naomi Osaka is three years her junior, and her relative lack of experience is reflected in her being seeded six places below Keys. This is the furthest she has ever got in a Grand Slam tournament, so there is no question she is something of an unkown quantity now.
Madison Keys of the United States celebrates after winning her women's singles quarter-final match against Carla Suarez Navarro
Image credit: Getty Images
ORDER OF PLAY DAY 11 - FULL SCHEDULE
Arthur Ashe Stadium Day session (Midnight UK start)