In 2006, she represented Germany along with Nicolas Kiefer at the Hopman Cup. She went on to win her first title at the Abierto Mexicano Telcel in Acapulco and completed a career best showing at Roland Garros, by reaching the quarterfinals, where she lost to Justine Henin. Her ranking peaked at 14, and remained in the top 20 for much of the year, despite a significant drop in results in the latter half of the season, as the German failed to progress beyond the quarterfinals of most tournaments. She split with Font de Mora in September 2006 and began to work with Dirk Dier.