Five Matches To Watch
 Simona Halep vs.  Ekaterina Makarova
Halep holds a 3-1 head-to-head record against Makarova, with the Russian’s only win over the Romanian coming at the 2015 Australian Open – but it would be a big mistake to underestimate Makarova. The nearly six-foot tall lefty has reached two Grand Slam semifinals in singles, won three doubles majors and a gold medal. Halep will have her work cut out for her.
Andrea Petkovic vs. Bianca Andreescu
After 17-year-old Bianca Andreescu became the first player born in the 2000s to snag a win over a top-20 player with her straight sets drubbing of No. 2 seed Kristina Mladenovic, she told the media: “My dream was to make history, and that’s what I did!” Petkovic, who is 12 years Andreescu’s senior, has experience on her side, but you can never underestimate a player who has nothing to lose. Andreescu will be looking to put icing on her D.C. cake.
 Milos Raonic vs.  Jack Sock
Stadium Court action will be as hot as the temperatures on Day 5, with No. 3 seed Raonic taking on Sock to open the day. Raonic, a champion here in 2014, has an 8-2 head-to-head record over the American, but Sock took won their most recent meeting in a third set tiebreak last fall in Shanghai. The speedy Stadium Court surface will be a benefit to Raonic’s serve and Sock’s forehand, and with just nine points separating them in the rankings (10 and 19, respectively), it could go down to the wire.
 Alexander Zverev vs. Daniil Medvedev
Daniil Medvedev is on fire. Ranked No. 99 in the world to start the year, the 21-year-old Russian reached a career-high rank of No. 48 in July – a number he will likely surpass when he leaves D.C. He’s already taken out No. 14 seed Steve Johnson and No. 4 seed Grigor Dimitrov this week – is world No. 8 Zverev next? Zverev, 20, won in straight sets the last time they faced off in 2016, but both players have matured since then. One thing is for sure: the ATP’s Next Gen is living up to the hype.
Genie Bouchard/Sloane Stephens vs. Nigina Abduraimova/Patricia Maria Tig
There’s no shortage of singles action on Friday, with all quarterfinal matches going down on Day 5. But don’t forget to check out the doubles! Thanks to Thursday’s rain, the dream team of Genie Bouchard and Sloane Stephens could potentially play twice today. Grand Slam champions Jamie Murray and Bruno Soares, Lukasz Kubot and Marcelo Melo, Henri Kontinen and John Peers are some of the other doubles stars on the schedule.