At the 2008 Olympic Games in Beijing, she arrived as the world-record holder and favourite for the gold medal in the 400 m freestyle, having set the Olympic record in the heats (4:02.19), but only finished 5th in the final. On the same day, she recovered from that disappointment by setting a world record (1:55.45) in the heats of the 200 m freestyle; in the final, she broke her own world record (1:54.82) and won her first Olympic gold medal.