Jade Jones claimed her first major tournament since winning gold at London 2012 with victory at the German Open.
Jones, who lost in the first round at last month's Trelleborg Open in Sweden, narrowly beat Russian Daria Zhuravleva 13-11 to claim the -57kg title.
"After the disappointment of losing in Sweden I was determined to do well here," said the 19-year-old.
Fellow Briton Bianca Walkden failed to seal five Open wins in a row, losing to Olga Ivanova in the +73kg semi-final.
The Russian prevailed on golden point after Walkden, who missed out on Olympic selection last year, trailed 5-4 at the end of round two.
Flint-born Jones dropped only four points in her quarter- and semi-finals before edging out Zhuravleva in a thrilling final in Hamburg.
"Now it's all about my preparations for the World Championships. I only got silver last time and I'd love to win gold," said Jones.
Nottingham-born Ruebyn Richards also claimed gold with his first A-Class tournament success on Saturday, beating Turkey's Muhammet Talha Sari.
He won six fights in all, including two by sudden death, after dropping down a weight division.
The 20-year-old, who won bronze at -80kg in Sweden last month, said: "I feel comfortable at -74kg because I am a small -80kg player.
"I fought [Serbia's] Damir Fejzic [in the semi-final] who had been a -68kg at the Olympics. I knew I would be able to outmuscle him.
"But he was stronger than I expected and fortunately I just managed to beat him."
Martin Stamper won gold in the -68kg weight division, beating fellow Briton and European champion Michael Harvey in the semi-finals.
Harvey's bronze was matched by Damon Sansum in the -87kg class as Britain enjoyed a successful tournament.
Liverpudlian Stamper, who narrowly missed a medal at the London 2012 Olympics, beat Harvey 9-4 in their semi-final before seeing off Russia's Vasilii Nikitin 11-4 in the final.
"I am so glad to be fighting at my best again," said Stamper. "This is one of the toughest opens in the world.
"I hope it can be a stepping stone for me to be at the top of the world championship podium in July."
In the junior event on Saturday, Britain's Nishaan Landa claimed gold at -59kg, Tim Needham won silver at -45kg and Natasha Burdock finished with bronze at -42kg, while on Sunday, Scottish teenager Asia Bailey took gold at -44kg and Plymouth's Katie Bradley captured a -42kg bronze.
