Laura Bechtolsheimer and her intended London 2012 horse Mistral Hojris took the Dortmund Grand Prix with a score of 81.17%.
Several of the German A squad trailed in her wake as Bechtolsheimer wasted no time underlining the strength of
Britain's bid for Olympic medals this summer.
Bechtolsheimer was part of the Great Britain European gold medal-winning team alongside Carl Hester, Charlotte
Dujardin and Emile Faurie in Rotterdam last August.
And her outstanding partnership with Mistral Hojris also resulted in them securing three silver medals at the 2010
World Equestrian Games.