Olympic champion Belinda Bencic earned a quick victory just eight days after a US Open quarter-final loss to Emma Raducanu, with the Swiss top seed advancing in at the WTA Luxembourg event on Thursday.
Bencic, ranked 12th, defeated Kazakh Zarina Diyas, 6-1, 6-3 in an hour.
The No. 105 challenger had her only chance on a break of the Swiss serve for 2-1 before Bencic proceeded to sweep five of the next six games on the way to the quarters.
The winner was lethal on first serve, winning 22 of 25 at the tournament where she played the 2018 final against Julia Goerges.
Victory set up a revenge chance for Bencic, who will next face a re-run of the spring Berlin title against 48th-ranked Italy-based Russian Liudmilla Samsonova, who defeated her in the German capital.