Monica Puig made history by beating Angelique Kerber in the women's singles final, while Juan Martin del Potro and Rafael Nadal played out a classic in the men's semis on day eight of the Rio Olympics.
World number two Kerber was much fancied to continue a fine year - that has yielded an Australian Open title and a Wimbledon final - against underdog Puig.
But Puig, ranked 34th in the world, won Puerto Rico's first Olympic gold medal courtesy of a 6-4 4-6 6-1 triumph at the Rio Tennis Centre.
It was a deserved victory for an emotional Puig, who had already beaten Garbine Muguruza and Petra Kvitova en route to the final.
In the women's singles bronze medal match, Kvitova beat the United States' Madison Keys in three sets.
There was guaranteed success for Czech Republic in the women's doubles bronze medal match, Lucie Safarova and Barbora Strycova triumphing over compatriots Lucie Hradecka and Andrea Hlavackova.
Del Potro was a singles bronze medallist four years ago in London, but has been injury-plagued in the intervening years.
However, he pulled out all the stops to beat Nadal in an epic semi-final to leave him one match away from winning a gold medal for his beloved Argentina.
Winning gold will be no easy feat, though, with defending Olympic champion Andy Murray awaiting in the final.
The Briton, who won Wimbledon last month, was in ominous form as he saw off Japan's Kei Nishikori 6-1 6-4.
MATCH OF THE DAY
The match of the day was undoubtedly the second men's semi-final between Nadal and Del Potro, who ultimately triumphed 5-7 6-4 7-6 (7-5).
Del Potro surrendered a break lead in the first set and was also a break up in the decider, but Nadal showed typical resilience to stay in the contest.
The Spaniard enjoyed plenty of support from the crowd and was all too happy to whip up a frenzy, but ultimately the 2008 singles champion - who also won doubles gold in Rio on Friday - could not deny Del Potro victory.
QUOTES OF THE DAY
"So many things come to mind. More than anything my family and the people who made sure I never quit the sport in spite of the bad times. Now I'm starting to understand that I will win a medal." - Del Potro starts to recognise the gravitas of his win over Nadal.
"It's not the medal I wish but still it's silver, and before I came here I said to myself I would do everything to win a medal and I won a silver one and I'm proud to represent my country and to take an Olympic medal back home." - A disappointed Kerber reflects on the consolation of a silver medal.
"I always have been 100 per cent loyal to where I was born and the roots I was raised in. I still have family in Puerto Rico and I have been back to visit quite a lot. I think it honestly is my favourite place to go when I want to go to the beach or see family." Puig, raised in Miami, still has close connections to Puerto Rico.
On Sunday, Murray attempts to defend his Olympic men's singles title against Del Potro, while Switzerland's Martina Hingis and Timea Bacsinszky battle Ekaterina Makarova and Elena Vesnina of Russia in the women's doubles final. The mixed doubles final will be an all-American affair, Venus Williams and Rajeev Ram up against Bethanie Mattek-Sands and Jack Sock.