Britain's Georgia Davies set a new European record in the heats of the women's 50m backstroke in Glasgow.
The 27-year-old, who won Commonwealth Games bronze in April, touched the wall in a new record time of 27.21 seconds.
The Welsh swimmer – a two-time European medallist in the event – will compete in the semi-finals later on Saturday.
"That's crazy," Davies told BBC Sport. "I wanted to do a strong heat as the field is quite strong, but I didn't expect a personal best."
Meanwhile, British cyclist Katie Archibald will race for her second gold medal in two days after reaching the women's individual pursuit final.
Scot Archibald will face Germany's Lisa Brennauer in Saturday evening's final, having won team pursuit gold on Friday.