Britain's Adam Peaty warned the men's 50m breaststroke world record could fall again in a fierce battle over the sprint distance in Wednesday's final.
The British ace broke his own world record from 2015 by clocking 26.10 seconds in Tuesday's heats, then lowered it again to 25.95sec in the evening's semi-finals.
The record is under threat for a third time at the world aquatics championships in Budapest with two-time gold medallist Cameron van der Burgh and 2015 bronze medallist Kevin Cordes also in the mix.
Depite shattering the world record twice on Tuesday, the 22-year-old Peaty says he can go faster in the final.
"There's always more to come, everyone says you work 10 out of 10, but it's really a nine to take it a step further," said Peaty.
Having failed in his bid to complete 'project 56' over 100m -- he swam 57.47sec in Monday's breaststroke final -- Peaty succeeded in breaking the 26-second barrier over the shorter distance.
"After the Rio Olympics, everyone was talking about 'project 56', I thought 'go on then'," he said.
"Then this morning it was 'project 26', I just dived in tonight and it felt good, but it's nothing without the gold."