Tokyo Olympics: Titmus wins duel in the pool as Dressel launches gold rush

Tokyo - Norway's Kristian Blummenfelt won the men's triathlon in a race marred by a bizarre false start

Australia's Ariarne Titmus won a thrilling 400m freestyle duel with American great Katie Ledecky in the Olympic pool on Monday as Caeleb Dressel launched his bid for a seven-gold spree in style.

The Tokyo Aquatics Centre also witnessed a dominant 100m breaststroke swim by world record holder Adam Peaty, who defended his title to give Britain their first gold medal of the Games.

Elsewhere on the third day of action in Tokyo, Norway's Kristian Blummenfelt won the men's triathlon in a race marred by a bizarre false start.

British diver Tom Daley shed tears of joy after winning his first Olympic gold in his fourth Games when he and partner Matty Lee edged out hot favourites China in the men's synchronised 10m platform event.

Ledecky came to Japan on the back of winning four gold medals and a silver at Rio in 2016, but Titmus has been snapping at her heels, ousting her as world champion in 2019 and topping the timesheets this season.

Titmus inched clear over the final 50m to touch in 3min 56.69sec after an absorbing encounter. Only world record holder Ledecky has ever gone quicker.

"I tried to stay as composed as I could and use the speed that I have," said the Australian, whose win was celebrated wildly by her coach, who ripped off his mask and gesticulated.

"To pull it off in the backend against someone who has an amazing second half of her race, I'm really proud of that."

The United States team spearheaded by Dressel stormed to the men's 4x100m relay gold medal in the third-quickest time ever to close the morning session.

Zach Apple brought them home after Dressel led off, with sizzling legs from Blake Pieroni and Bowen Becker ensuring they touched in 3:08.97, ahead of Italy and Australia.

It could be the start of a seven-title spree for Dressel, 24, whose 13 world titles have prompted inevitable comparisons with Phelps -- winner of eight golds in 2008 and 23 in total.

The unstoppable Peaty extended his dominance of the 100m breaststroke event, powering to the line in 57.37sec ahead of Dutchman Arno Kamminga while Canada's Maggie MacNeil dethroned Sarah Sjostrom to win the women's 100m butterfly.

In the diving pool meanwhile there was a long-awaited gold medal for Daley after China's Chen Aisen and Cao Yuan, both already twice Olympic gold medallists, botched their fourth dive of six.

Britain took a third gold of the day when Tom Pidcock won the mountain bike cross-country title.

Japan skateboard double

Elsewhere on Monday, Japan's Momiji Nishiya became one of the youngest gold medallists in history with victory in the inaugural women's skateboarding competitions.

Nishiya -- aged just 13 years and 330 days -- edged out another 13-year-old, Brazil's Rayssa Leal, who took silver and 16-year-old Funa Nakayama, who won bronze.

Nishiya's win came a day after Tokyo-born Yuto Horigome won gold for Japan in the men's skateboarding street competition.

Norway's Blummenfelt won the triathlon following a farcical start when around two-thirds of the 56 competitors dived into the water and set off on the swimming leg only to be hauled back.

The bungled start was caused by a media boat filming the competitors before they dived in for the 1.5-kilometre swimming leg.

Blummenfelt, 27, crossed the line in a time of 1hr 45min 04sec before raising the winning line tape above his head and then throwing himself to the ground in celebration.