Hunt on Tankers Town during the cross-country round
Britain's Sharon Hunt earned her first four-star win at the HSBC FEI Classics three-day event in Luhmuhlen, Germany.
The 32-year-old picked up only four faults on Tankers Town in the final showjumping round to prevail by 0.2 penalties from German Ingrid Klimke.
"I can't believe it - I am shocked," said Hunt after claiming the £27,500 first prize.
Briton Oliver Townend achieved the world championships qualifying standard by finishing fifth.
Reigning Classics champion Townend, though, was disappointed to miss out on a podium finish on board Ashdale Cruise Master.
The World Equestrian Games is the aim
"There is still room for improvement - I would prefer his dressage to be five marks better, for instance - but he is getting better and better all the time," stated the Yorkshireman.
Devon-based Lucy Wiegersma took sixth and ninth respectively on Woodfalls Inigo Jones and Granntevka Prince, while Mary King (Apache Sauce) was seventh.
The day belonged to Kent-based Hunt, however, who has significantly boosted her chances of being selected for September's World Equestrian Games in Lexington, Kentucky.
"My mindset has changed a little this year," added Hunt, who also won at Chatsworth and Belton Horse Trials earlier this year.
"I knew I was good enough for the team, and I wanted to make a real go of it. The World Equestrian Games is the aim."
Hunt is also in contention for the overall £92,000 Classics prize.
Along with fellow Briton William Fox-Pitt and Australian Paul Tapner, Hunt is only seven points behind German leader Andreas Dibowski, who finished third in Luhmuhlen.
The Classics series resumes in September at the Burghley Horse Trials in Lincolnshire before concluding in Pau, France later this year.