Jakub Majerski notched a winning time of 51.06 in the 100m fly in his native Poland, beating the 51.32 he produced for bronze at the 2024 World Championships.
The American quartet of Hunter Armstrong, Nic Fink, Claire Curzan and Kate Douglass won mixed medley gold by nearly three seconds in a time of 3:40.22.
The women's breaststroke events will be among the deepest at the Doha World Championships, with Ruta Meilutyte and Kate Douglass highlighting the fields.
Arno Kamminga won the 100 breast (56.49) over Caspar Corbeau (56.90) as both swimmers finished under Corbeau's previous meet record from prelims (57.51).
Olympic Champion Maggie MacNeil will make an appearance in Athens, the 2nd of 3 stops on the World Cup circuit and joins a competitive field in the sprints.