Nick Kyrgios reached the Atlanta Open quarter-finals as Alexandr Dolgopolov was beaten on Thursday.
Kyrgios, who suffered a shock first-round loss in Toronto, returned to some form with a 7-6 (7-4) 6-3 win over Jared Donaldson.
The Australian second seed served nine aces and broke three times in a match interrupted by rain early on.
The second-round win saw Kyrgios set up a clash against Fernando Verdasco, the Spanish fifth seed who crushed Julien Benneteau 6-1 6-3.
Dolgopolov was a surprise loser as the Ukrainian fourth seed went down to Yoshihito Nishioka 6-3 2-6 6-1.
Nishioka will face Horacio Zeballos, who brushed past lucky loser Tobias Kamke 6-1 6-4.