Helen Glover and Heather Stanning retained their Olympic women's pair crown in impressive style on a day of double gold for Great Britain at Lagoa.
The duo took gold at London four years ago, and Friday's victory extends their unbeaten run that stretches back five years as they pulled well clear inside the first 500 metres to set the platform for their triumph.
Silver went to New Zealand duo Genevieve Behrent and Rebecca Scown, while bronze was claimed by Denmark's Hedvig Rasmussen and Anne Andersen.
Glover and Stanning's success was followed up by their compatriots in the men's coxless fours, who held off the challenge of Australia and Italy to cross the line first. GB have now topped the podium in that event in each of the past five Games.
The two sets of double sculls medals were also decided, with Maaike Head and Ilse Paulis clinching glory for Netherlands in the women's race, ahead of Canada and China.
In the men's event, France's Pierre Houin and Jeremie Azou were triumphant, with Ireland's O'Donovan brothers Gary and Paul taking silver ahead of Are Strandli and Kristoffer Brun of Norway.
The way Stanning and Glover rowed away from the competition in the first 500m was a sight to behold, effectively sealing their win inside the opening quarter of the race.
Earlier, victory for Head and Paulis in the women's double sculls was met by a number of jubilant fans jumping into the water, swimming out to their boat and attempting - unsuccessfully - to capsize the athletes.
QUOTES OF THE DAY
"You never know, we've got our families to think about. Now I have to plan a wedding!" - Glover to BBC Sport when asked if they would go for three straight Olympic crowns.
"This week's been an emotional week. I'm not a very emotional person, but I'm going to have to change that after this week." - Stanning struggles to keep her feelings in check.
"We are so happy. A little tired, but more happy than tired. Can't use words. It's beautiful." - France's Houin is almost lost for words after glory in the men's double sculls.
Saturday sees the conclusion of the rowing programme, with the two single sculls finals preceding the men's and women's eight showdowns.