Delray Beach - Second seed Tommy Haas of Germany advanced to the quarter-finals of the $455,775 ATP Delray Beach International Championships with a straight-sets triumph on Thursday.
Haas ousted Uzbek Denis Istomin 6-4, 6-1, moving on in 67 minutes without facing a break point.
Next for Haas will be a Friday quarter-final against the winner of a later match between Russian Evgeny Donskoy and Croatian Ivan Dodig, one of four second-round matches rained out on Wednesday.
US top seed John Isner was to face Japan's Go Soeda in a night match with the winner to face either South African sixth seed Kevin Anderson or Taiwan's Lu Yen-Hsun on Friday.
Lithuanian lucky loser Ricardas Berankis advanced to the last eight by rallying to defeat American Jack Sock 3-6, 6-4, 6-1.
Berankis will next face France's Edouard Roger-Vasselin, who eliminated Croatian Ivo Karlovic 6-4, 7-5.
Spanish qualifier Daniel Munoz outlasted Belgium's Xavier Malisse 7-6 (7/3), 3-6, 6-3 to reach the last eight, where he will face the winner of a later match between Latvian Ernests Gulbis and US third seed Sam Querrey.