Justin Rose of Great Britain captured the first men's Olympic golf gold medal since 1904, securing a two-stroke victory over Sweden's Henrik Stenson in a thrilling battle that went down to the final hole.
Ekaterina Makarova and Elena Vesnina of Russia won women's tennis doubles gold, while Bethanie Mattek-Sands and Jack Sock defeated Venus Williams and Rajeev Ram in an all-American mixed doubles final.
Jemima Sumgong became the first Kenyan woman to claim Olympic marathon gold by winning an enthralling race in a time of two hours, 24 minutes 04 seconds.
Great Britain won their first and second men's Olympic gold medal in gymnastics, Max Whitlock taking out the floor final ahead of Brazilian duo Diego Hypolito and Arthur Mariano and following it up with pommel horse glory.
American Simone Biles' march into Olympic history continued with an individual vault triumph to go with her team and individual all-around successes.
QUOTES OF THE DAY
"I knew whatever happened I couldn't lose the gold and then I knew I was on the way to history." - women's marathon winner Jemima Sumgong of Kenya on her moment of destiny.
"Oh my God. That felt better than anything I've ever won. It was the best tournament I've ever done. It felt like a cross between a golf tournament and a carnival. It was unique, incredible. If they want to cut golf from the Olympics, I'd ask 'Were you in Rio?'." - Olympic golf gold medallist Justin Rose.
"They pulled out their guns, they told the other swimmers to get down the ground. I refused, I was like, 'we didn't do anything wrong, so I'm not getting down on the ground'. And then the guy pulled out his gun, he cocked it, put it to my forehead and he said, 'get down'. And I put my hands up, I was like 'whatever'. He took our money, he took my wallet. He left my cell phone, he left my credentials." - Ryan Lochte, as quoted by NBC, claims he played it incredibly cool after being threatened by armed robbers posing as police officers.
Gabby Douglas was the gymnastics star of the London Olympics in 2012, but she has been thoroughly upstaged by Biles in Rio. Adding insult to injury, Douglas' mother claims her golden girl has been tormented by accusations of showing a lack of patriotism during the national anthem. Spare a thought for the 20-year-old, who help the United States win the team all-around gold earlier in the Games.
"Gabrielle's had her heart broken, but she knows she still has a job to do for Team USA," Douglas' mother Natalie Hawkins said.
Great Britain were the big climbers early on Sunday, rising above China and into second overall behind the United States, with Germany fourth and Russia fifth.
COMING UP -
The men's 100m final will take centre stage as Usain Bolt attempts to take gold in the event for the third successive Games, while Andy Murray takes on Juan Martin del Potro in the men's singles tennis gold medal match.
The men's 400m precedes that show-stopper, while there are also medals up for grabs in fencing, weightlifting, wrestling and cycling.
In what could be a good omen for Usain Bolt, the Jamaican superstar sprinter's football team, Manchester United, made a winning start to their 2016-17 Premier League campaign under new manager Jose Mourinho.