It's the first all-American quarterfinal line-up at an ATP event since Orlando in 1991, which was more than five years before any of the Houston quarterfinalists were born.

Auger-Aliassime had two chances to wrap up his seventh career singles title in straight sets, but was ultimately pushed to the limit in a 6-2, 6-7(7), 7-6(2) win.

Aleksandar Kovacevic, Ekaterina Alexandrova and Ann Li scored upset wins in Montpellier, Linz and Singapore.