It was a good day to be a seed at the Badminton World Federation (BWF) Swiss Open as very few of the top-ranked players in action were not victorious.
Olympic champion Carolina Marín was among them, defeating Russia's Natalia Perminova 21-8, 21-10 to reach the second round of the women's singles in Basel.
Dane Julie Dawall Jakobsen, who beat Swiss player Sabrina Jaquet in three games, is up next for the Spanish three-time world champion.
Estonia's Kristin Kuuba pushed Thai third seed Pornpawee Chochuwong to three games, but lost 21-17, 18-21, 18-21.
World champion PV Sindhu of India, Danish fourth seed Mia Blichfeldt and fifth seed Busanan Ongbamrungphan all won in straight games.
Only one seeded player - number eight Kim Ga-eun of South Korea - lost in the women's singles, beaten by Ongbamrungphan's Thai team mate Supanida Katethong.
All eight seeds won in the men's singles and India's Srikanth Kidambi stood out as the only one not to do so in straight games, but overcame compatriot Sameer Verma 18-21, 21-18, 21-18.
Verma was the champion in Basel in 2018.
Top seed Viktor Axelsen of Denmark opened his tournament by beating Canada's Jason Ho-Shue 21-17, 21-7.
English pair Chloe Birch and Lauren Smith - seeded fourth in the women's doubles - were the day's highest-ranked casualty.
Danes Freja Ravn and Amalie Magelund saw them off 21-15, 21-18.
With BWF events in Europe few and far between because of the pandemic, the Swiss Open boasts a strong field and last-16 matches are scheduled tomorrow in men's and women's singles and doubles, plus mixed doubles quarter-finals.