Helen Glover and Heather Stanning never take anything for granted but felt they had "stepped on" in their world cup semi-final which they won convincingly in the Swiss rain this afternoon.
"Today was a step on. We always tend to improve through the regatta", said Glover.
"I'm looking forward to tomorrow's final. It will be tough but we're definitely looking forward to it", added Stanning.
But theirs was not the most eye-catching GB performance of the day as GB pulled off an exciting one-two in the repechage of the open men's double scull.
Jonny Walton and John Collins won the race in style in GBR 1, leading throughout. Behind them Nick Middleton and Jack Beaumont, in GBR 2, were lying third and seemingly out of a qualifying slot until a startling final 200m surge took them past the Australians by a sliver and into the final.
We had a really good race in today's repechage. We got out strongly and got in control of the race and put our stamp on it. It was really pleasing to get that dominance", said Collins.
Walton said: "Tomorrow will be the first time that we won't be racing a final from an outside lane. We hope to demonstrate what we've been doing in training".
"I think we timed it perfectly and just wanted to make everyone excited", said Beaumont with his trademark humour afterwards.
"It was a real crowd pleaser and it's nice to be in the A Final", added Middleton.
Beaumont is back racing this season after a serious training accident last summer after which he needed extensive treatment for a back injury in Portugal and back at Reading's Berkshire Independent Hospital before mounting a remarkable recovery.
Alan Campbell showed significant improvement on his European performance to each the final. "I did it by the skin of my teeth by just two tenths of a second in third place from the Belarusian. We've had a great day for GB scullers".
In the final race of the afternoon session, the GB lightweight men's double scull of Richard Chambers and Will Fletcher became the tenth GB crew through to the finals from 14 entered. They were beaten by Norway but showed they have the pace to challenge tomorrow.
Brianna Stubbs and Ellie Piggott, in the light women's double, put in a strong first half but paid for that early pace, slipping to fifth and will race a B final, as will the second-ranked GB open women's pair who were sixth in today's semis.
Later this evening the lightweight men's pair of Joel Cassells and Sam Scrimgeour, already European Champions, will race a final in this international class boat.
RACE REPORTS
The GB duo of Helen Glover and Heather Stanning began their semi-final as they meant to carry on. They were fast out of the blocks and had a length lead over the French, South Africans and Americans within the first 300m.
With heavy rain falling in still conditions, the Olympic and World Champions stretched out their lead and had clearwater with 500m gone.
South Africans Kate Christowitz and Ann-Lee Persse were neck and neck with the Americans Felice Mueller and Grace Luczak at halfway after which the Americans emerged into second. Neither could catch the GB combination who went on to win in 7:04.24.
Britain's second crew in this race came home in sixth. Louisa Reeve and Vicky Meyer-Laker were a last-minute combination who raced here as spares for the eight and came into the semis via yesterday's repechages.
"It was good, we got closer to the Chinese than yesterday and there was definitely an improvement", said Meyer-Laker.
GB also had two crews in the repechage of the men's double scull this afternoon. Jonny Walton and John Collins were racing at the top-ranked combination with Nick Middleton and Jack Beaumont in Great Britain 2.
Walton and Collins struck early and were leading from a tightly-packed field at the first timing point with 500m gone. With only two places available for tomorrow's final the battle was always going to be intense.
Australians Christopher Morgan and David Watts were holding second at halfway but were being challenged by Middleton and Beaumont as well as the USA.
With Collins and Walton secure at the head of the field, the Australians seemed to have nailed down second but Middleton and Beaumont had different ideas. They picked up the pace and surged through in the final 200m to take second and a place in tomorrow's final in 6:23.07 to the winning time of 6:21.23.
In the ensuing men's single scull semi-final Britain's Alan Campbell had a bright first 500m. He was tucked in close behind the multi-medalled Ondrej Synek of the Czech Republic and holding second place.
Cuba's Angel Fournier Rodriguez was pressing him from lane five and came through in the second half to take second behind Synek. Campbell looked secure in third and held onto that place by just two-tenths at the line, having missed the final surge from the Belarusian.
Richard Chambers has recovered from injury, has been back training and for the first time this season has been racing internationally in Lucerne with Will Fletcher. They were third in their heat to qualify for today's semis.
Starting with speed, they took an early lead but were being chased down by the Norwegians Kristoffer Brun and Are Strandli who beat them in the heats. Ultimately the Norwegians went on to win but the British crew showed they have the speed to be strong podium contenders tomorrow.
Brianna Stubbs and Ellie Piggott are part of a strong GB lightweight women's sculling squad and will carry their race experience from here forward potentially to the World Championships later this summer. In today's semi-final they were not the fastest starters but built themselves back into fourth place at the initial timing point.
In the second quarter they slipped back, marginally, behind Ireland. Canada were the race leaders with China in second. Ultimately, the GB duo were fifth, the first half effort taking its toll.