The reigning Olympic and world champions, the US (pictured top) cruised home in dominant fashion to qualify first for the final from their heat, recording a time of 6min 15sec.

It was here that the Americans were last beaten, all the way back in 2006, but the US eight, which consisted of Caryn Davies, Caroline Lind, Eleanor Logan, Meghan Musnicki, Taylor Ritzel, Esther Lofgren, Susan Francia and Erin Cafaro, as well as cox Mary Whipple, were never threatened by either Australia or Britain.

The Australians edged out the British eight for second, but both, as well as Germany, were forced to go through the repechage if they want to make it to the final.

Canada also reached the final after winning their heat, with Romania and the Netherlands brushed aside, but intriguingly they beat the American time by less than a second.

The clash between the North American rivals in the final promises to be a thrilling one.

The most exciting race of the day came in the men's lightweight double sculls heats.

Zac Purchase and Mark Hunter, defending their Olympic title for Britain, were pushed all the way by the New Zealand pair of Storm Uru and Peter Taylor.

Zac Purchase and Mark Hunter (second from bottom) en route to victory 

The British pair led for most of the race, but never by more than half a length or so, although the result meant both made it through to the semi-finals.

It was the perfect response to being beaten by New Zealand at the last World Cup regatta in Munich, and Hunter said it was important to get off to a good start.

"When things aren't going so well and you're not working well as a unit, you go back to basics," he said.

"We sat in each other's positions to see what the other was going through, what the others were thinking.

"We've done all the hard work and strength in the gym and now it's good to get back to racing.

"It's a starting point, not an end product.

"There's still more to come but it's a good place to work from."

They will be joined in the semi-final by Italy's Pietro Ruta and Elia Luini, who came from behind to edge out Portuguese duo Pedro Fraga and Nuno Mendes.

It was an exceptionally tight race at the end, with the Italians forcing their way into the lead during the sprint for the finish.

Also making it through to the semis from the remaining two heats were Denmark's Mads Rasmussen and Rasmus Quist, Norwegians Kristoffer Brun and Are Strandli, France's Jeremie Azou and Stany Delayre, and the German pair of Linus Lichtschlag and Lars Hartig.

Sophie Hosking and Kat Copeland celebrate an impressive triumph

Sophie Hosking and Kat Copeland were also impressive after storming to victory after leaving the rest of the field trailing in their wake during the heats.

The form of the British women was enough to ensure that the crowd was not disheartened any further after rain began to fall at the start of their race, as the pair emerged as real medal contenders.

Louise Ayling and Julia Edward had started well for New Zealand but were eventually beaten by Danish pair Anne Thomsen and Juliane Elander Rasmussen, in their bid to reach the semis.

In the second heat Greece's Christina Giazitzidou and Alexandra Tsiavou dominated and won by over two seconds from Australia's Bronwen Watson and Hannah Every-Hall.

The third heat saw Chinese pair Dongxiang Xu and Wenyi Huang finished almost four seconds ahead of Germany's Lena Mueller and Anja Noske, as both dominated, with the next boat another 11 seconds adrift.

Contact the writer of this story at [email protected]