Tokyo 2020 day two: Olympic gold winners after a stunning victory for Tunisian teen

18 golds were up for grabs on Sunday, led by 18-year-old Ahmed Hafnaoui

Tunisia's Ahmed Hafnaoui celebrates after winning the final of the Men's 400m Freestyle.

Chase Kalisz of Team United States celebrates winning gold in the Men's 400m Individual Medley.

Yui Ohashi, of Japan, wins the final of the women's 400-meter Individual Medley.

Emma McKeon, Meg Harris, Cate Campbell and Bronte Campbell of Australia celebrate on the podium after winning the Women's 4 x 100m Freestyle Relay.

Yuto Horigome of Team Japan on his way to gold in Skateboarding Men's Street Final.

Vitalina Batsarashkina of Team ROC poses during the medal ceremony of the 10m Air Pistol Women's event.

Shi Tingmao and Wang Han of China claim gold in the Women's 3m Springboard Synchro.

Anna Kiesenhofer of Team Austria celebrates winning the gold medal in the Women's Road Race.

China's Li Fabin on his way to victory in the Men's 61kg Weightlifting.

San An, Minhee Jang, and Chaeyoung Kang of South Korea pose with their gold medals for the women’s team archery.

Japan's Uta Abe, of Japan, left, celebrates after defeating Amandine Buchard, of France in the women's -52kg gold medal judo match.

Gold medallist and Olympic record holder William Shaner of Team United States poses on the podium during the medal ceremony for the 10m Air Rifle Men's event.

Lee Kiefer of Team United States after winning the women's foil individual fencing gold.

Silver medalist, Gergely Siklosi of Team Hungary, gold medalist Romain Cannone of Team France and bronze medalist Igor Reizlin of Team Ukraine during the medal ceremony for the men's epée individual fencing.

Hifumi Abe, of Japan, celebrates after defeating Vazha Margvelashvili, of Georgia, in the men's -66kg gold medal judo match.

United States's Anastasija Zolotic, left, celebrates with coach after winning gold in taekwondo women's 57kg category.

Ulugbek Rashitov of Team Uzbekistan celebrates after defeating Bradly Sinden of Team Great Britain during the Men's -68kg Taekwondo gold medal contest.

Gold medalitst Lijun Chen of China celebrates on the podium after the men's 67kg weightlifting event.

Day two of the Olympics in Tokyo saw a big surprise in the swimming as Tunisian Ahmed Hafnaoui pulled off a thrilling victory in the men's 400m freestyle.

The 18-year-old Hafnaoui, in the outside lane after being the slowest in qualifying, produced a blistering finish to pip Australia's Jack McLoughlin to gold.

Hafnaoui's victory is only the fifth by a Tunisian athlete at the Olympics, but their third in swimming, and he was left stunned by his performance.

"I just can't believe it. It's a dream and it became true. It was great. it was my best race ever," he said.

There were 18 medal events on Sunday, in archery, cycling, diving, fencing, judo, shooting, skateboarding, swimming, taekwondo and weightlifting.

Games chiefs, already struggling to contain Covid, have another threat to contend with as Tropical Storm Nepartak headed towards Tokyo, with the weather agency saying it was due to arrive on Tuesday.

As a "protective measure" organisers have brought forward to Sunday rowing events that had been scheduled for Monday and said they were following the track of the storm.

All the gold medal winners will be added to the picture gallery above as they take their place on the podium.