Sanislas Wawrinka booked his spot in the quarter-finals of the Suisse Open in Gstaad with a 7-5 7-6 (7-4) win over Daniel Gimeno-Traver.
The second seed was made to work for the success in front of his home fans, being broken on two occasions and taken to a tie-break in the third set, but he eventually came out on top after an hour and 34 minutes.
Wawrinka will next play fifth-seeded Spaniard Feliciano Lopez, who progressed from the second round following a 6-4 6-3 win against Andrey Kuznetsov.
Elsewhere, fourth seed Juan Monaco made it safely into the last eight with a 6-1 6-2 victory over Guillermo Garcia-Lopez.
Argentine Monaco took just 64 minutes to complete the victory at the clay-court tournament, breaking his Spanish opponent's serve four times in the process.
Monaco will face sixth seed Mikhail Youzhny in the quarter-finals after the Russian overcame a scare to win 6-3 4-6 6-3 against Pablo Andujar.
Youzhny suffered a setback as he lost the second set but eventually made it past his nervy opponent, who served nine double faults.
Top seed and home hero Roger Federer does not start his campaign until Thursday.