Another spellbinding night of athletics action at the Stade de France saw the United States add to their gold medal tally thanks to a stunning last leg from sprint star Richardson in the women's 4x100m relay.
The USA's highly fancied men's relay quartet however finished empty-handed after a disastrous performance saw them disqualified, with Canada storming to a memorable victory.
In the women's 10,000m, Kenya's Beatrice Chebet completed a long-distance double with her second gold medal of the games, four days after triumphing in the 5,000m.
It was a masterful performance from the diminutive East African known as the 'smiling assassin', who timed her finish to perfection to scamper home in 30min 43.25sec, ahead of Italy's Nadia Battocletti (silver) and Sifan Hassan of the Netherlands.
The women's shot put saw Germany's Yemisi Ogunleye snatch a dramatic gold medal with her final attempt, a last-ditch heave of 20.00m taking her past New Zealand's Maddison-Lee Wesche, who threw 19.86.
In the men's triple jump, Spain's Jordan Diaz won gold with a jump of 17.86m, with Portugal's Pedro Pichardo taking silver and Andy Diaz of Italy claiming bronze.
There were golds too for the Dominican Republic's Mari Marileidy Paulino in the women's 400m, while the men's 400m hurdles saw the United States add to their gold tally with Rai Benjamin outfoxing Norway's Karsten Warholm to claim gold.
Heptathlon history
In the heptathlon meanwhile, Belgium's Thiam became the first woman in Olympic history to win three consecutive gold medals, adding to her titles from Rio in 2016 and Tokyo in 2021.
Thiam finished with 6,880 points to finish just ahead of Britain's Katarina Johnson-Thompson who took silver with 6,844.
In a thrilling finale, Thiam needed to finish within eight seconds of Johnson-Thompson in the last event, the 800m.
Johnson-Thompson dug deep to cross in 2min 04.90sec, but a weary Thiam scraped home inside the eight-second window in 2:10.62.
It marked an astonishing return to the podium for Thiam, who was forced to miss last year's World Championships with an Achilles injury.
"I don't think I can describe it," Thiam said after her win. "It's a mix of everything that I've lived. I could use a thousand words.
"If you didn’t live every single day with me for the past two, three, four years, you couldn't understand what I feel right now.
"But it's unique, and I think that the main feeling is pride. I’m very proud of myself."
Friday's action had got underway with the USA's 4x100m women's relay squad scorching to gold in 41.78sec ahead of Britain in 41.85sec and Germany in 41.97sec.
Richardson had been left with a seemingly hopeless situation, collecting the baton for the final leg in fourth position.
But she raced through the gears and blasted past her rivals to claim gold for herself and team-mates Melissa Jefferson, Twanisha Terry and 200m gold medallist Gabby Thomas.
"I just remembered trusting my third leg, trusting Gabby, knowing that she's going to put this thing in my hand and to leave my best on the track," Richardson said.
But while the women celebrated, the much-fancied US men's 4x100 squad were disqualified from the final, the latest in a long line of Olympic flops.
The US men have not won a 4x100 relay medal since taking a silver in Athens 20 years ago. Their latest debacle - a botched first changeover between Christian Coleman and Kenny Bednarek - earned a scathing rebuke from US sprint great Carl Lewis.
"It is time to blow up the system," said Lewis. "This continues to be completely unacceptable."
In the men's 400m hurdles, Benjamin avenged his defeat to Warholm in the 2021 Tokyo Olympic final with a victory in 46.46sec to take gold.
Warholm tied up badly towards the end of the race, claiming silver in 47.06sec, with Brazil's Alison Dos Santos bronze in 47.62sec.
