Three-time Olympic champion Adam Peaty marked his World Championship comeback by qualifying fastest for the men's 100m breaststroke final in Doha.
The Briton, at his first Worlds since 2019 after breaks to deal with periods of depression and problems with alcohol, swam 58.60 seconds in his semi-final to reach Monday's final.
Peaty, 29, is seeking to add to his eight world gold medals.
Meanwhile, GB's men missed out on a medal in the 4x100m freestyle relay.
China's victory included a world-record time for 100m freestyle in the first leg of the relay by 19-year-old Pan Zhanle, who clocked 46.80.
Britain's relay team of Jacob Whittle, Tom Dean, Duncan Scott and Matt Richards qualified for an Olympic quota spot with their heat performance. The team were disqualified from the event at the 2023 World Championships for an early take-off.
Britain also qualified for another final, with Abbie Wood the seventh-fastest semi-finalist in the women's 200m medley with a time of two minutes 11.35 seconds. American defending champion Kate Douglass was the fastest qualifier in 2:08:41.
Peaty improves on heat to qualify fastest
Peaty, a dominant force in breaststroke events for almost a decade, became the first British swimmer to retain an Olympic title when he took gold in the 100m at the Tokyo Games in 2021.
He missed the 2022 World Championships because of a foot injury, and was unavailable last year after stepping away from the sport to prioritise his mental health.
The world record holder told the BBC last week he had arrived in Doha "at peace" after his difficulties.
While some top swimmers are skipping the championships to focus on Paris 2024, Peaty is using the event as part of his preparations for his bid for a third successive Olympic 100m gold in the French capital this summer.
Having qualified third fastest in the heats to reach the semi-finals, Peaty improved his time to finish as the fastest qualifier for the final, ahead of American Nic Fink (58.73) and the Netherlands' Arno Kamminga (58.87).
"I feel good," Peaty said after qualifying for the final. "My objective for this meet was to progress through the rounds, progress physically and in results, but also progress mentally and see what strategies are working, what isn't working.
"It's more of a test event for us, but obviously we're going to put our best foot forward and put a good fight on.
"After the heats I was like, 'okay, I know what I'm working with and I know what I'm capable of'. But tonight was just about going out there, showing a little bit of Adam Peaty which is a front end, getting a little bit angry with myself like I normally do. Tonight I showed that I can still get it down that back end when I really need to."
Fellow Briton James Wilby went out in the heats.