US' Katie Ledecky and Australia's Ariarne Titmus react after a heat of the women's 400m freestyle. GETTY IMAGES

A mouthwatering 400m women's freestyle opened the first full day of sporting action at the Olympics on Saturday after a soggy but spectacular opening to the Games in Paris. 

All eyes were on the Paris La Defense Arena for the women's 400m freestyle —one of the most-anticipated events of the entire Olympics involving three swimmers who have held the world record.

Canadian teenage sensation Summer McIntosh took the early lead in her heat with New Zealand’s Erika Fairweather hot on her heels. Conservative Mcintosh eventually finished with a 4:02.65 behind the New Zealander who clocked in 4:02.55.  

In heat three Katie Ledecky and Ariarne Titmus went head-to-head with Ledecky finally pulling ahead with 4:02.19 and Titmus clocking in at 4:02.46.

While fourteen golds were up for grabs, the number was swiftly reduced to 13 early Saturday as the wet weather which deluged Friday night's opening ceremony along the River Seine continued to cause headaches. 

The first to come in the mixed-team 10-metre air rifle finals with tennis, badminton, rowing, cycling, hockey and basketball getting underway along with the surfing competition, nearly 16,000 kilometres (9,950 miles) kilometres away on the French Pacific island of Tahiti.



Though the biggest focus will be on the men's doubles, with Alcaraz teaming up with 14-time French Open champion Rafael Nadal in a Spanish dream pairing. 

Chinese shooters Huang Yuting and Sheng Lihao will start as favourites for the first gold of the Games after a dominant victory at last year's world championships in Baku.

French rugby fans will flock to the Stade de France to see if Dupont can lead the host nation to gold in rugby sevens. France however must overcome South Africa in Saturday's semi-finals to reach the gold medal match against the winner of the other last-four clash between holders Fiji and Australia.

The men's street skateboarding competition, due to take place at the Place de la Concorde in the historic heart of Paris, was postponed until Monday due to rain overnight, organisers said.  

Yuto Horigome of Japan is defending his skateboarding street crown as he aims to fend off challengers including Nyjah Huston of the United States and France's Aurelien Giraud.