With Annie Vernon substituting in the bow seat for Rebecca Romero, who has a back strain, they led a new German combination over the line. Russia won the other heat, faster than the British over the first half of the course, but slower over the second.
Romero, Sarah Winckless, Frances Houghton and Catherine Grainger had earned maximum points in the first two rounds of the Cup at Eton and Munich, although attempts to win at Versailles and Henley were thwarted by catching a boat-stopping crab at the French regatta and having to miss Henley because of an injury to Winckless.
The men's coxless four remain unbeaten after winning their heat comfortably yesterday. Steve Williams, Peter Reed, Alex Partridge and Andy Hodge secured the lead with a quick start which enabled them to experiment with a different way of rowing.
"We raced a little bit differently,'' said the British coach, Jürgen Grobler, who formed the crew in May. "It is to build up confidence using technique and harmony rather than just going flat out. I think they did it quite well and had the discipline to do it today.''
Alex Gregory's regatta ended when he was lifted out of his boat after suffering an asthma attack during the last 1,000 metres of his heat in the double sculls. Although fully recovered, the boat was withdrawn from the afternoon's rêpechage.
Despite the mishap, Gregory and his partner, Colin Smith, finished third behind the winners, Luka Spik and Iztok Cop of Slovenia, the Olympic silver medallists. Gregory and Smith are new to the senior team this year, and have been selected for the Under-23 World Championships in 11 days' time.
The two Wests, Kieran and Josh, secured a semi-final place in a spaced-out heat of the coxless pairs, and the lightweight coxless four also avoided the rêpechage round when they chased Ireland over the course and took the third qualifying place in a neck-and-neck struggle with Poland.