Haislett was the first American woman to defeat a swimmer from East Germany in the 100-meter freestyle since the 1972 Summer Olympics; she did so at the 1990 Goodwill Games in Seattle, Washington. At the 1991 World Aquatics Championships in Perth, Western Australia, Haislett won the 100-meter freestyle, and swam the anchor legs for the winning U.S. teams in the 4×100-meter freestyle and the 4×100-meter medley relays, ending the East German women's eighteen years of overwhelming dominance in the 100-meter freestyle at the world championships. Haislett also endured the emotional agony of disqualifying her team on an early exchange in the 4×200-meter freestyle relay – a relay race that the American women won in the water.