NBC Olympics.com – Sweden's Sarah Sjostrom, the reigning world champion, set the Olympic record in the 100m butterfly in Saturday's but missed her own world record by about two-tenths of a second. Sjostrom clocked 55.84 to advance to Sunday's final in first place.
Team USA's Dana Vollmer, the 2012 Olympic champion in the event, qualified in fourth place with 57.06 seconds.
Fellow American Kelsi Worrell missed the final, finishing in ninth place by 0.03 seconds.
Earlier in Saturday's preliminary heats, Vollmer went a best time since she gave birth to her son Arlen, which she did in March 2015.