Corey Main set two personal bests in qualifying for the finals of the 100m backstroke at the world swimming champs in Budapest.
The 21-year-old secured his first world championships final with a 53.76s effort in the semifinal to be eighth fastest to qualify for the final.
Earlier the US-based swimmer from the Howick Pakuranga club went 53.93s, to edge under his previous best, to be ninth fastest from the heats.
In the semifinal Main started conservatively, but powered home in 53.76 to further lower his personal best.
Wellington's Emma Robinson, from the Capital club, secured a personal best finishing 11th fastest in heats of the 1500m freestyle.
The Queensland-based swimmer clocked 16:25.78 in her heat, more than five seconds better than her previous best and and means she has improved over 40 seconds in the last six months in this new Olympic event.
The Rio Olympian Matthew Stanley was a disappointing 14th fastest in heats of the 200m freestyle in 1:48.02, failing to qualify for the final, despite having been in strong form in the lead-up to the championships.
US-based North Canterbury swimmer Natasha Lloyd was 29th of 48 starters in the 100m breaststroke while 17-year-old Gabrielle Fa'amausili from the United club in Auckland was 26th fastest of 59 starters with a personal best in the heats of the 100m backstroke.
There's only one swimmer on the programme on day three of competition is Bradlee Ashby who'll compete in the 200m butterfly.