New Zealand's Erika Fairweather bounced back from her shock disqualification in the 400 metres freestyle to post the fastest time in the 200 heats on day three of the world championships in Singapore on Tuesday.
Fairweather's 400 title defence was ruined by a false start in Sunday's heats but the 21-year-old had no trouble in the shorter distance, leaving Olympic champion Mollie O'Callaghan in her wake at the World Aquatics Championships Arena.
Fairweather, runner-up in the 200 at last year's championships in Doha, charged into the Singapore semis with a time of one minute and 56.54 seconds, 0.20 better than American Erin Gemmell and a half-second quicker than third-fastest O'Callaghan.
Tunisia's Ahmed Jaouadi, the 1 500 freestyle short course world champion, took top seed in the men's 800 in 7:41.58, ahead of Australian Sam Short, who took silver in the 400 on Sunday.
Ireland's Olympic gold medallist Daniel Wiffen sneaked into the final along with Paris 400 champion Lukas Maertens, who beat Short for the world 400.
Italy's Simone Cerasuolo was fastest into the men's 50 breaststroke semifinals (26.42), while American Luca Urlando was quickest into the men's 200m butterfly semifinals (1:52.71).
Five gold medals are up for grabs in the evening session, with American great and world record holder Katie Ledecky favourite to claim a sixth 1 500m freestyle crown and record-extending 22nd world title.
Olympic champion David Popovici will go for gold in the men's 200 freestyle, while Australia's backstroke queen Kaylee McKeown will battle American Regan Smith for the 100 title.
American Kate Douglass, the Olympic 200 breaststroke champion, will look to add the world 100 title to her collection.