That is an improvement on Australian Kaylee McKeown's three-year-old record by 23 hundredths.
Curtis took bronze in the 100-meter freestyle on Tuesday, but now goes into the final on Thursday as a strong favourite for gold.
Hubert Kos of Hungary and David Popovici of Romania took expected victories in the 200-meter backstroke and 100-meter freestyle, respectively.
Kos was close to the world record in the semifinals on Tuesday and held world-record pace for 150 metres in the final, but faltered at the end and was just over a second behind in 1:53.08.
Kos has previously won Olympic and world championship gold in the event and has now completed the championship treble.
