The Tokyo Olympics delivered a day of high drama on Sunday with a stunning surprise in the pool, one of the great David v Goliath cycling victories and double sibling judo gold as Japan continued their golden start.

Tunisia are unlikely to add to their solitary gold but no medal of the Games will be celebrated more wildly than that earned via the astounding achievement of 18-year-old Ahmed Hafnaoui, who stunned the swimming superpowers with victory from lane eight in the men's 400m freestyle.

"It's a dream and it became true - it was my best race ever," Hafnaoui said in an Olympic-level understatement after he held off heavily-fancied Australian Jack McLoughlin and American Kieran Smith despite qualifying slowest for the final.

Hafnaoui received the ultimate validation as American medal machine Michael Phelps, the greatest swimmer in history, labelled his performance as an "unbelievable swim". “The difference between these Olympics and the past is that every single person in the final has a chance of winning gold," said Phelps.

Skateboarder Horigome, who grew up in the Tokyo ward where the event is being held, took gold https://www.reuters.com/lifestyle/sports/skateboarding-horigome-wins-first-olympic-gold-skateboarding-2021-07-25 at the Games debut of a sport once seen as a symbol of counter-culture and, ironically, still symbolised by the "no skateboarding" signs plastered on the outside walls of the venue.

"It felt significant to return to Koto ward, it meant so much more for me," said Horigome, who moved to the United States after high school to follow his skateboarding ambitions.

The day the Abe family will never forget began when Uta triumphed in the women's 52kg category. The 21-year-old had cruised through to the final but was then taken deep into Golden Score overtime before overcoming Amandine Buchard of France.

Hifumi, 23, won gold in the men's 66kg final against Georgia's Vazha Margvelashvili.