Francesca Halsall enjoyed a dominant victory in the 50m freestyle final on the opening night of the British Championships.
Her time of 24.47 seconds in Sheffield was well inside the qualifying time for next month's World Championships.
Halsall finished just 0.08 seconds off the podium in the event at the London Olympics after struggling with a shoulder injury ahead of the Games.
There were also victories for Robbie Renwick, Adam Brown and Dan Sliwinski.
Halsall's Loughborough University team-mate Amy Smith, who finished second, also swam a time which should secure her a place in the squad for the World Championships in Barcelona, touching in 24.98 seconds.
"My job was to qualify and I've done that and I'm happy," Halsall told BBC Sport.
"This year my main focus is on developing my sprinting so the 50m and the 100m events are something that I'll look at over the next few years leading into Rio."
It was the eighth time Halsall had claimed the 50m freestyle British title and with her shoulder now stable she is hoping for further success this summer.
"I'm consistently around the top three in the world at the moment, so if I can keep that going and have a little more rest hopefully I'll be able to step it up in Barcelona," stated the former European champion.
"I'm really looking forward to going because James [Gibson, Halsall's coach] won gold there 10 years ago so the pressure is on our squad now to get some medals!"
Sliwinski's victory in the 50m breaststroke final turned out to be an emotional one for the swimmer.
The 2010 Commonwealth bronze medallist missed the London Olympics after needing knee surgery and has been relying heavily on his parents after having his funding axed later that year.
"I pretty much broke down [after London] but my family have been my rock," said Sliwinski, whose time of 27.40 was a new British record.
"I haven't done the training, I'm barely touching 1500m a week which is nothing, but I never doubted myself and I had to show British swimming that I'm a racer."
A record also tumbled in the men's 50m freestyle with US-based London Olympian Adam Brown breaking Mark Foster's long-standing time of 21.96 set in 2008, with 21.92 in the final.
"It's unbelievable," Brown - who like Sliwinski is also unfunded - told BBC Sport.
"It's been in the back of my mind since 2008 and I've been chipping off the time so it's great to achieve that goal now."
Scotland's Commonwealth 200m freestyle champion Renwick survived a late charge by open water specialist Daniel Fogg to claim victory over 400m.
Both swimmers were under the three minutes 48.61 second world championship qualification time and will expect to be named in the squad next week.
Highlights on the second day of the British Swimming Championships include a first chance to see world short course champion Hannah Miley compete in her favoured 400m individual medley event, while 50m world champion Liam Tancock will contest the 100m backstroke final.