Charlotte Worthington ensured a dramatic start to Sunday's Olympic action with a thrilling gold medal in the women's BMX park freestyle final while Duncan Scott continued to help Great Britain make history in the pool.
Worthington recovered from a fall on her first run to to land a ground-breaking 360-degree backflip on the second and post a winning score of 97.50.
Declan Brooks followed up with a bronze in the men's event to earn Britain's fourth BMX medal in Tokyo.
The medal rush also continued in the swimming pool as GB clinched their eighth in Tokyo with silver in the men's 4x100m medley relay.
That makes it their most successful Games and means Scott has won more medals at a single Olympics than any other British competitor.
The 24-year-old, who signs off with a gold and three silvers, was part of a quartet including Adam Peaty, Luke Greenbank and James Guy that were pipped to the title by the USA.
British boxer Ben Whittaker also guaranteed himself at least a silver medal by beating Imam Khataev, of the Russian Olympic Committee, to reach Tuesday's 81kg final.
Pat McCormack will also fight for gold in the men's welterweight division after Ireland's Aidan Walsh pulled out of their semi-final with an ankle injury, while Frazer Clarke reached the super-heavyweight final after France's Mourad Aliev was disqualified.
Britain's BMX medal bonanza
Worthington said she was trying to find a "big banger trick" to deliver Olympic gold but an unprecedented 360-degree backflip left her on the floor during run one.
Undeterred, the 25-year-old went on to execute the move in her second run, becoming the first woman to land it in competition, and registering a score of 97.50.
"It was incredible," said Worthington, who watched on as four rivals - including hotly tipped American Hannah Roberts - failed to usurp her mark.
"I've not been doing that trick for so long but we've been trying to find that big banger trick and when we did we thought, 'this is the one'. If it wasn't for Hannah Roberts we wouldn't be doing these tricks or be this far."
It was the culmination of years of hard work for Worthington, who was a late convert to BMX and had been working as a chef "sweating it out in the kitchen for over 40 hours a week" before concentrating on the sport.
"It's a lot of hard work paid off. On the bike, yes, it's physical hard work but I feel like the work on myself has paid off," she added.
Having watched that drama unfold, Brooks added Britain's fourth BMX medal - after Bethany Shriever and Kye Whyte in the racing - to cap an incredible Games.
"I've just cried for the last couple of minutes," 25-year-old Brooks told BBC Sport after his bronze was confirmed.
Slam Dunc for GB swimmers
Regular visits to the podium at the Tokyo Aquatics Centre this Games have seen Britain establish themselves as one of the sport's powerhouses in Japan.
They may still be a distant third on the medal table to the USA and Australia, but an eighth trip to the podium marks the nation's most successful Olympics.
The American team needed a world record time of three minutes 26.78 seconds to beat the British quartet to the men's 4x100m medley relay title.
But a silver medal rounded off a superb Games for Britain, who finish with four golds, three silvers and a bronze having earned a solitary gold at Rio five years ago.
It also capped a record-breaking Olympics for Scott, whose four medals are record haul for a Briton at a single Games and take him to six overall.
Only Bradley Wiggins, Chris Hoy and Jason Kenny have won more.
"I have a lot of good team-mates," Scott told BBC Sport. "I'm very fortunate to be part of some excellent relay teams."
The US victory means American superstar Caeleb Dressel joins compatriots Michael Phelps, Mark Spitz and Matt Biondi, as well as East Germany's Kristin Otto, as the only swimmers to win five golds at a single Olympics.
Meanwhile, Australia's Emma McKeon made history as the first female swimmer to win seven medals at an Olympics, claiming four golds and three bronze.
What is still to come on Sunday?
Athletics: Zharnel Hughes leads Team GB's medal bid in the men's 100m final (13:50)Gymnastics: Max Whitlock competes in the men's pommel horse (10:44)Sailing: Alison Young competes in the Laser Radial medal race (TBC)Hockey: Great Britain men's team face India in the quarter-finals (13:00)
