Campbell beat former world champion Marcel Hacker

Double sculling duo Annie Vernon and Anna Bebington were another surprise as they snatched victory from Germany.

Great Britain's men's coxless four just survived a late surge from Germany to win their 14th successive race.

And the women's quadruple scull, with Debbie Flood a new arrival this year, beat Australia by four seconds.

Of the seven other Great Britain crews in finals on Saturday, there were bronzes for Mark Hunter in the lightweight single and lightweight pair Nick English and Dave Currie.

Campbell, from Coleraine, came home ahead of former world champion Marcel Hacker of Germany in his senior debut in the event, while Olympic champion Olaf Tufte of Norway was fourth.

"It was a bit of a surprise but my hard work and perseverance paid off," said Campbell.

"I want to win so badly, my muscles go into top gear and the sprint just comes to me.

"This is the start of my assault on the Olympics in Beijing, the first step towards my goal of Olympic gold."

Vernon and Bebington were particularly impressive in their first World Cup appearances.

"We're renowned for being powerful in the last 500 metres so it was just a question of putting it into practice," said Vernon.

Meanwhile Flood said: "It's nice to be back in the quad, good to have a win in the first race and that's how we mean to carry on."

The next World Cup event begins in Poznan, Poland on 15 June, with the World Cup finals in Lucerne in July.

But the focus already is set on peaking for the World Championships, to be held in England for the first time in 20 years, from 20-27 August.

Veteran Sarah Winkless was with Flood in the quad scull and warned: "This is not the finished product from us.