It was a youth day at the world swimming championships.

Canada’s Summer McIntosh, 15, won gold in the 200-metre butterfly on Wednesday to claim her first world title. Shortly after, David Popovici, a 17-year-old Romanian, grabbed his second.

Both will need to row a lot more to catch Katie Ledecky, who won her 18th world championship gold medal as part of the American quartet that won the women’s 4x200m relay. At the age of 25, Ledecky found herself with 21 medals after extending her record as the most decorated female swimmer in the history of the competition.

Popovici won the men’s 100 freestyle after winning the 200 freestyle on Monday. He became only the second man to achieve the 100-200 double in a world championship after American Jim Montgomery in 1973. He is also the first Romanian swimmer to win two gold medals in a world championship.

“The airport will be chaos, but I’m ready for the reception,” said Popovici, anticipating the return to Bucharest. “For Romania it means a lot and I like how they value it.”

McIntosh, 15, clocked 2:05.20 – a junior world record in the 200 butterfly to beat three Olympic medalists.

“One of my big dreams was to become world champion, especially in the 200m butterfly. It’s something I’ve always wanted because it’s one of my favorite tests,” said McIntosh, who edged Hali Flickinger of the United States by 88 seconds and Zhang Yufei of China. by 1.12.

Popovici, who broke the junior world record in the 100m with a time of 47.13, had to fight hard to beat Frenchman Maxime Grousset by six hundredths in the final with a time of 47.58.

Canadian Joshua Liendo Edwards, who led until the semi-final of the final, took bronze.

The United States won its 11th gold medal in Budapest when Claire Weinstein, Leah Smith, Ledecky and Bella Sims beat the Australian quartet by 2.41 seconds and the Canadian quartet by 3.31 in the 4x200m.

The United States (11 gold, six silver, nine bronze) and Australia (two gold, five silver and one bronze) have won at least one medal in each of the five days.

Kylie Masse won Canada’s second gold medal of the night by winning the 50m backstroke in 27.31 – eight hundredths ahead of American Katharine Berkoff and nine hundredths ahead of France’s Analia Pigree.

Masse became the first Canadian swimmer, male or female, to win three gold medals at a world championship.

For his part, Frenchman Léon Marchand won the 200m medley with a time of 1:55.22. The American Carson Foste and the Japanese Daiya Seto complete the podium.

It was the second gold medal for Marchand, 20, in this world championship. He won the 400m medley on Saturday, coming close to breaking Michael Phelps’ world record.