McIntosh, who won three gold medals a year ago at the Paris Olympics, holds the world record in the 400 free — 3:54.18. She will face off again with Ledecky in the 800 free later in the meet, probably the most anticipated race in Singapore.

Katie Ledecky returned to the top of the podium at the World Aquatics Championships after delivering a gold medal-winning performance in the 1,500-meter freestyle.

Summer McIntosh continued to take the swimming world by storm on Monday, winning her second gold medal in two days to keep up her bid to make World Aquatics Championship history.