PARIS (Reuters) - Summer McIntosh showed the Paris Olympic pool the thrill of the new with a second gold medal for Canada on Thursday, but it was golden oldie Katie Ledecky standing alone at the end of day six as the most decorated female swimmer of all time.
McIntosh swept in like a summer storm to make off with the 200 metres butterfly title at La Defense Arena before Ledecky took a record 13th Olympic medal, helping the United States take silver behind Australia in the women's 4x200m freestyle relay.
Ledecky's achievement was another boost for the U.S. team following Kate Douglass's gold in the 200m breaststroke.
Hungary savoured their first champion of the meet when the Bob Bowman-coached Hubert Kos took gold in the men's 200m backstroke.
The men's swimming has been all about French poster boy Leon Marchand, but 17-year-old McIntosh may end up remembered as the face of the women's meet.
Having blown away the field for the 400 metres individual medley gold on day three, her second gold was more of a battle in the event her Olympian mum Jill Horstead swam for Canada.
She had to reel in the eventual bronze medallist and Chinese defending champion Zhang Yufei, then fended off America's Regan Smith who took the silver, to win by 0.81 seconds with a time of 2:03.03.
She also became the first Canadian woman to win three individual medals in swimming at an Olympics, and another may be coming in the 200m individual medley.
"It's pretty cool tonight winning the 200 fly just because that was by far her main event," McIntosh said of her mum.
"So sharing that moment with her is pretty cool."
In McIntosh, Ledecky might see something of herself in the teenage tearaway shaking up the swimming world.
The 27-year-old American showed she is far from a spent force, however.
Swimming a strong third leg of the relay to help the U.S. onto the podium, Ledecky's 13th medal moved her past the previous record of 12 shared by Jenny Thompson, Dara Torres, Natalie Coughland and Emma McKeon.
Ledecky, who already retained her 1,500m title, may charge further ahead when she goes for an unprecedented fourth gold in the 800m freestyle in Paris. A home Games at Los Angeles in 2028 also beckons.
South Africa's Tatjana Smith, however, was content to call time on her career after taking silver behind the versatile Douglass in the 200m breaststroke.
Having taken the 100m gold in Paris and built her Olympic medal tally to four, Smith, also 27, bows out of the sport as South Africa's most decorated Games swimmer.
Kos, the 2023 world champion, celebrated his first Olympic gold in the backstroke with a swim of 1:54.26 seconds, 0.56 ahead of Greek silver medallist Apostolos Christou, with Swiss Roman Mityukov taking the bronze.
Australia capped the night with the 4x200m relay gold, three years after a selection mistake left them with bronze and a storm of criticism at Tokyo.
Three golds are up for grabs on day seven on Friday, highlighted by Marchand's bid for a fourth gold medal of these Games in the 200m individual medley (IM).
The French swimmer complained he was hurting after his epic, two-gold night on Wednesday but he still managed to top qualifying for the 200 IM final on Thursday to the delight of home fans.
"I'm going to try to recover now because I'm out of juice," he said.
"I'm going to approach it like the other races, except this time it will be my last chance to live a moment like this.
"I'm going to have my eyes wide open."
Australia's former world champion Cameron McEvoy will go for the men's 50m freestyle gold, while compatriot and defending champion Kaylee McKeown will look to complete an unprecedented "double-double" in women's swimming by retaining both her Olympic backstroke titles.
With the 100m backstroke gold already won, McKeown qualified second into the 200m final behind American Phoebe Bacon.
(Reporting by Ian Ransom; Additional reporting by Rohith Nair, Steve Keating and Alan Baldwin; Editing by Hugh Lawson)