Sarah Sjöström held the world record for 100 metres butterfly for nearly eight years.
Tonight, it was beaten by Gretchen Walsh during the American Olympic trials in Indianapolis – and already in the semi-final.
55.18 is the time to beat now.
But it will not be done by the Swedish swimming queen. She no longer competes in this distance.
I thought I was going to die, I didn't know it could go that fast, says Walsh according to the AP news agency.
It's an unreal experience. I'm trying to convince myself that it really happened, she continues.
Sarah Sjöström set the world record for 100 metres butterfly as far back as 15 years ago. Since then, she has improved her times on several distances, most recently at the Olympic Games in Rio de Janeiro in 2016.
Then, she clocked 55.48.
Gretchen Walsh, 21, from Nashville, Tennessee, can already improve the time in the final tonight.
I'm ready, says Walsh, who is primarily targeting a spot on the USA's Olympic team for the first time.
