Third seed Guillermo Garcia-Lopez booked his place in the quarter-finals of the Sofia Open in Bulgaria on Wednesday.
The world number 27 had too much for Bosnian qualifier Mirza Basic, breaking his opponent once in each set to complete a routine 6-3 6-4 win.
Slovakian seventh seed Martin Klizan also reached the last eight but was made to work harder for a 6-3 2-6 7-6 (4) win over Lukas Rosol.
Eighth-seeded Frenchman Adrian Mannarino, Lithuania's Ricardas Berankis and German qualifier Daniel Brands were all first-round winners.
Source: PA