The French Open champion pulled off a tweener to convert her first break point for a 3-2 lead in the first set at the grass-court tournament, then wrapped up the result in 1 hour, 19 minutes.
Swiatek had saved three break points in her opening service game and did not face another until her final service game of the match. She saved all five break points she faced, while taking four of her five opportunities against the 129th-ranked Swiss player.
“It’s getting easier every year to convert my clay-court style to more grass-court style,” said Swiatek, who is coached by Polish compatriot Tomasz Wiktorowski. “I think it will come with experience. I have a coach who knows how to coach players who are good on grass court like Aga Radwańska, so I’m pretty positive about my future on grass.”
Earlier, Katerina Siniakova beat Evgeniya Rodina 6-2, 6-4 to make her first quarterfinal appearance since returning from a wrist injury that kept her out for two months after the Miami Open on March 21.
Siniakova next plays second-seeded Liudmila Samsonova.
Lucia Bronzetti rallied to upset fourth-seeded Egyptian Mayar Sherif 1-6, 7-6 (2), 6-3 and move into her first quarterfinal on grass. The 65th-ranked Italian player next faces Varvara Gracheva of France.
Iga Swiatek into Bad Homburg Open quarters with straight-sets win