Katie Ledecky of United States in action [Source: Reuters]

Katie Ledecky shrugged off her disappointing 400 metres freestyle bronze to top qualifying for the 1,500m final at the Paris Olympics as Leon Marchand mania returned to a buzzing La Defense Arena.

Three days after coming a distant third behind Australian champion Ariarne Titmus and runner-up Summer McIntosh in the 400m, seven-times Olympic gold medallist Ledecky was fastest in the 1,500m heats in 15 minutes 47.43 seconds.

The time was nearly four seconds better than the second quickest swimmer, Italian Simona Quadarella, who was runner-up to Ledecky at last year’s World Championships in Fukuoka.

World record holder Ledecky won the inaugural women’s 1,500m at Tokyo three years ago and it would take a huge upset for her to miss out on another gold in the event in Paris.

Victory would see her match fellow American Jane Thompson’s all-time record of eight gold medals in Olympic women’s swimming, with still the 800m freestyle to come.

Home hope Marchand returned to the pool two days after being feted like a rock star by the Parisian crowd for blitzing the field for gold in the 400m individual medley.

The 200m butterfly world champion in Fukuoka eased into the semi-finals with the sixth fastest time in the heats and soon dived back in to be third quickest into the 200m breaststroke semis.

Olympic champion Kristof Milak of Hungary was fastest into the 200m butterfly semi-finals with a time of 1:53.92, while South Korean surprise package Cho Sung-jae took top seed for the 200m breaststroke.

Fresh from becoming Romania’s first men’s Olympic champion swimmer by winning the 200m freestyle, 19-year-old David Popovici was third into the 100m semi-finals behind American top seed Jack Alexy and Frenchman Maxime Grousset.

Evergreen Swede Sarah Sjostrom was fastest into the women’s 100m freestyle semi-finals ahead of Siobhan Haughey of Hong Kong.

Australia’s young gun Mollie O’Callaghan, who took the 200m gold from Titmus on Monday, qualified fifth.

Olympic champions Britain will head into the men’s 4x200m freestyle relay final later on Tuesday confident of going back-to-back.

They were fastest in the heats with a time of 7:05.11, ahead of the United States and France.

The Australian team suffered a blow with medal hope Lani Pallister ruled out of the women’s 1,500m freestyle after testing positive for COVID-19.

Pallister’s setback came after Briton Adam Peaty tested positive on Monday, hours after narrowly missing out on a third successive 100m breaststroke gold.

Australia’s Olympic champion Kaylee McKeown will defend her 100 metres backstroke title later on Tuesday in a showdown with American world record holder Regan Smith.

Also in evening session, Daniel Wiffen will hope to become the first Irishman to win an Olympic swimming gold in a hotly contested 800m freestyle final which includes reigning champion Bobby Finke of the U.S.