After beating Australian Kaylee McKeown's three-year-old record by 23 hundredths of a second in the semifinals on Wednesday, she struck again in the final.
Curtis, 19, swam in 26.56, improving her one-day-old record by seven hundredths.
Sara Curtis is also swimming the 50-metre freestyle at the European Championships and, in her record form, is a major challenger to Sarah Sjöström, who is the fastest in Europe this year.
