Team GB pair Katherine Grainger and Anna Watkins broke a 20 year old Olympic record in reaching the women's sculls final on Friday.
The duo, unbeaten in the past two years, went into their heat as overwhelming favourites for gold, and delivered a timely reminder to their Australian rivals, of Kim Crow and Brooke Pratley, who won heat two of the sculls.
The crews from New Zealand and Poland make up the four-strong final on Friday, likely to among a spate of gold medals from Eton Dorney this summer for Team GB.
"I'm really pleased with our first event. I'm overwhelmed with the result," Grainger said.
"You can hear the crowd but you feel it in your body, pulsing through you. We're very lucky to have this incredible support from around the country. It lifts you like nothing else.
"The plan for the next four days is feet up... not! We've got an adrenaline high now and we're both aware we can enjoy it for the next few hours, but we need to bring it back down. We'll head back to training and a dull lifestyle to get everything in place for Friday."
Elsewhere, the sports' blue ribbon event, the men's four, saw the expected dominance of the Australian and Great Britain crews come to fruition, with the former setting an Olympic record in reaching Saturday's final.
Sir Steve Redgrave, a former Olympic champion in the men's four, said: "It's what happens on Saturday in the final that is the important thing. We all know it's going to be nip-and-tuck between the Brits and the Aussies. I think Australia grabbing the Olympic record will ruffle our guys and it should help them.
"I'm very happy with our team. Everything seems to be coming together at the right time and everyone seems very classy and relaxed.
"We've won the gold three times running, and three of the guys in our four are reigning Olympic champions - that's why the men's four is the focus. But actually the Australians are the favourites, because they won the last major regatta.
"The Aussies look technically better and they move their boat better. If conditions stay as they are then I fancy Australia, but if the wind turns around Great Britain are my tip."
After falling foul to the German's over the weekend, Team GB's men's eight took full advantage in the repercharge, reaching Wednesday's final after edging the crews from Canada and Netherlands.
The women's quadruple sculls also reached the final at the second time of asking in the repercharge, finishing third behind Australia and United States to confirm a fourth final spot for Great Britain.