Before play kicks off, lets get to know a little bit more about Friday's competitiors.
- Five Americans - Taylor Fritz, John Isner, Steve Johnson, Tennys Sandgren and Jack Sock - have reached the US Clay quarterfinals for the second year in a row, and the third time since the event moved to Houston in 2001.
- This is also the second straight year that four past champions are among the final eight: John Isner (2013), Steve Johnson (2017), Ivo Karlovic (2007) and Jack Sock (2015).
- At 39-years-old Ivo Karlovic is the oldest US Clay quarterfinalist in the Open Era. He's the oldest quarterfinalist at an ATP World Tour event since 39-year-old Tommy Haas at Stuttgart in 2017, and is bidding to be the oldest semifinalist at an ATP event since 40-year-old Jimmy Connors at San Francisco in 1993.
- Tennys Sandgren, who reached the quarterfinals at the Australian Open, is bidding to reach his first career ATP level semifinal.
- The night session Friday features the singles and doubles champions from the Miami Open. John Isner will look to extend his winning streak to nine matches, while Bob and Mike Bryan will look to win their eighth match in a row.
- John Isner enters Friday's match with 9,981 career aces. He is bidding to be the fourth player to reach the 10,000 ace milestone, joining Ivo Karlovic (12,604 through two rounds here this week), Roger Federer (10,463) and Goran Ivanisevic (10,131). Isner has hit 364 aces in his 24 career US Clay matches.
- Six-time doubles champions Bob and Mike Bryan won 40th career US Clay match on Thursday and will be playing for a spot in their ninth final at this event. Friday night will be the 55th time the duo has faced Max Mirnyi. The Bryans own a 31-23 record against Mirnyi, who has faced them with 22 different partners.