Sjöström, who is making a championship comeback after becoming a mother last year, is the gold favourite in the event and also has Europe's fastest time (25.05) this year.
In the semi-final in Paris she clocked 25.12, the fastest by some distance. Second overall was Arina Surkova of Russia (neutral swimmer) with 25.44.
Sjöström's time was an improvement of 38 hundredths on her morning effort.
It's great fun to swim so fast. I've never competed so little before a championship so I know that the heats and semis will be a bit of a get-go race and then things will be set for the final, says Sarah Sjöström.
“Not prioritizing myself”
She has only competed in one 50-metre butterfly event since her comeback, in Rome in June, but everything seems to be going well.
The details that have made her unbeatable in the world at the distance. Sjöström has won six straight gold medals at the World Championships and five straight gold medals at the European Championships at the distance.
Her son Adrian, almost 1 year old, and her husband Johan are in Paris, which makes swimming life a little different for Sjöström than before.
When I swim, life is as usual, but it's different between races. I change nappies and when we get down to the buffet, I look for food for my son, then I don't prioritise myself. We have a son who sleeps quite well, he sleeps all night, so that's good, says Sarah Sjöström.
Aiming for a medal double
Sara Junevik made it to the final with the fourth-fastest time, and her 25.61 is her third-fastest time in her career at the distance, where her best is 25.50.
Could there be two Swedes on the podium on Wednesday night?
50 butterfly is truly a Swedish legacy, so I think we should try to fix that, says Junevik, who highlights Sarah Sjöström's return as significant.
"Having her in the call room calms my nerves, it's like before again. She's so relaxed," says Junevik, who is the reigning champion.
She won gold in the distance at the European Championships in Belgrade in 2024 - a championship that was decided in the weeks before the Olympics and without the big stars.
