Large parts of the Swedish team were affected by a nasty stomach bug.
Louise Hansson managed to avoid the infection.
In Monaco, she took her third consecutive win on the 100-meter butterfly in the Mare Nostrum tour.
Hansson clocked in at 57.04 seconds and was almost a second ahead of the second-place finisher, Frenchwoman Marie Wattel, who recorded 57.90.
Sweden can now look back on three consecutive wins (Canet, Barcelona, and Monaco) on the distance in the tour.
Seven Swedes did not start in Monaco due to the stomach bug. In addition to Hansson, Sarah Sjöström and Michelle Coleman also swam.
Sjöström once again swam under 24 seconds on the 50-meter freestyle.
She recorded 23.91 in the quarterfinals.
Sjöström was the fastest in all rounds on the 50-meter butterfly and 50-meter freestyle.
Next fastest on the 50-meter freestyle in the first two rounds was Michelle Coleman. In the quarterfinals, she had the third-fastest time.
The semifinals and finals will take place on Sunday. Coleman will swim both the 50-meter and 100-meter freestyle on Sunday.
Sara Junevik, Sofia Åstedt, and Robin Hanson, all three of whom are in pursuit of an Olympic spot, missed the competition due to the stomach bug.
