Sailors Dylan Fletcher and Stuart Bithell won Olympic gold as they started what Great Britain hope will be a medal rush on day 11 of Tokyo 2020.
Fletcher and Bithell clinched the men's 49er in a tense finish, pipping New Zealand's Blair Tuke and Peter Burling.
There is also the prospect of more British sailing medals, plus further chances in cycling, boxing and diving.
In one of the stories of the Games, Norway's Karsten Warholm won men's 400m hurdles gold with a new world record.
Warholm, 25, ran 45.94 seconds to win a final described as "truly unbelievable" by former British hurdler Colin Jackson.
Success for Fletcher and Bithell was Britain's 12th gold medal of the Games, a tally bettered only by China, the United States, Japan and Australia.
But earlier on Tuesday, another medal hope - British sprinter Adam Gemili - suffered injury heartbreak in the men's 200m.
A tearful Gemili said pulling up out of the blocks with a hamstring injury was "the worst feeling in the world".
Later, American gymnast Simone Biles will compete in the women's beam final (07:50 BST), having withdrawn from four other finals to protect her mental health.
A highly anticipated women's 200m final (13:50) sees Jamaican sprinter Elaine Thompson-Herah aiming to win a sprint double.
After already clinching 100m gold, she goes up against fellow Jamaican Shelly-Ann Fraser-Pryce, US sprinter Gabby Thomas - the fastest woman over 200m this year - and Shauna Miller-Uibo of the Bahamas.
What else is coming up on day 11?
Athletics: British trio Keely Hodgkinson, Jemma Reekie and Alex Bell will be on the start line together in the women's 800m final (13:25).Boxing: Britain's Pat McCormack, the 2019 world silver medallist, takes on Cuba's Roniel Iglesias in the men's welterweight final (11:05), while flyweight Galal Yafai could guarantee himself a medal (09:30).Cycling: Could this be Britain's best day in the velodrome? Both Laura and Jason Kenny will be in action as the women's team pursuit (09:26) and men's team sprint (09:44) medals are decided.Diving: British duo Jack Laugher and James Heatly go in the men's individual 3m springboard final (07:00).Gymnastics: Joe Fraser is a medal threat for GB in the parallel bars on the final day of artistic gymnastics (09:00).Sailing: Defending champion Giles Scott goes in the Finn class medal race (06:30-07:00).'Worst feeling in the world' - injured Gemili out of 200m
Gemili, 27, saw his hopes of a medal dashed after injuring his hamstring in the final block start of his warm-up before going out for the heats.
He had been aiming to improve on his fourth place at Rio 2016, where he missed out on bronze by three thousandths of a second.
"I felt my hamstring go. I'm in so much pain. I said I just wanted to go out there and try. You have to try," said Gemili, who was fighting back the tears during his trackside interview.
"I can't believe it happened. I felt I had a good chance. It's the worst feeling in the world."
How has Team GB fared so far on day 11?
Canoeist Deborah Kerr, 23, missed out on a medal in her first Olympics, finishing eighth in the women's kayak single 200m as New Zealand's Lisa Carrington, 31, continued her dominance by winning a third consecutive gold.
"At least two girls either side could have been a winner so I knew it would be really tough. I'm really proud I've made it in," said Kerr.
Long jumpers Jazmin Sawyers, 27, and Abigail Irozuru, 31, were unable to win a medal as Germany's Malaika Mihambo took gold.
Boxer Caroline Dubois, 20, narrowly lost on points to Thailand's Sudaporn Seesondee in the women's lightweight quarter-final, missing out on the guarantee of at least a bronze medal.
