Third-seeded Guillermo Garcia-Lopez of Spain routed Damir Dzumhur of Bosnia 6-1, 6-1 to reach the quarterfinals of the Zagreb Indoors on Thursday.
Garcia-Lopez saved five break points to reach his second quarterfinal in 2015, after reaching the last eight in Chennai in the first week of the season.
Dzumhur was broken in the first game and struggled throughout to deal with his opponent's forehand.
Garcia-Lopez will face seventh-seeded Viktor Troicki from Serbia, who eased past Go Soeda from Japan 6-3, 6-1 in less than an hour. Troicki won 96 percent of points on his first serve and never faced a break point.
Andeas Seppi of Italy also advanced to the quarterfinals by defeating James Ward of Britain 7-5, 6-7 (4), 6-3.