Donald Young was the only seed to make it through to the Memphis Open quarter-finals on Thursday after seeing off Marcel Granollers in straight sets.
American Young - the third seed - overcame Granollers 6-1 7-6 (7-2) as he reached his first quarter-final of the season.
A semi-finalist last year, Young opened the match by dropping serve but he won the next sixth-consecutive games to take control of proceedings at the ATP 250 event.
Granollers stepped it up a gear in the second set but he was no match for Young, who closed it out in a tie-break.
"This year, it's the best I've played, even though I haven't played many matches," said the 26-year-old.
"I didn't want to go three. Anything could happen in the third if he got momentum."
The win earned a showdown with Ricardas Berankis, who stunned eighth seed Damir Dzumhur 6-3 6-4.
Berankis - the world number 102 - broke Dzumhur three times in the opening set before sealing his spot in the last eight after breaking to love.
Australian seventh seed John Millman also crashed out following a straight-sets loss to Benjamin Becker.
The in-form Millman was upstaged 6-2 7-6 (8-6) by the German.
Teenage wildcard Taylor Fritz will play Becker after reaching his first ATP Tour quarter-final via a 7-6 (7-5) 7-6 (9-7) victory against fellow American Steve Johnson.