In her debut year in the 5* ranks, the young German piloted Iron Dames My Prins in just her 2nd WC class and her horse's first-ever jumpoff.
The American won his third major class of the show; two Canadians in the jump-off, with Tiffany Foster finishing second riding Electrique.
American rider Alex Matz added to his win column aboard Cashew CR on Friday night in the $85,680 Centennial Cup.
The pair took the two-day, three-round National 1.40m Jr/Am Jumping Championship for the third year in a row.
After this third qualifier in France, Gregory Wathelet (BEL) leads the World Cup Western European League standings.
The American was also awarded Leading International Rider honours at the event which ran at the Kentucky Horse Park, Oct. 29-Nov. 03.
The German took the 5* Qualifier at MLSJ Monterrey with Otello de Guldenboom while the Canadian was close riding De Flor 111 Z Santa Rosa.
The Brit piloted the small but speedy black stallion to the fastest of just eight double-clears over Guilherme Jorge-designed track.
The pair won the Longines FEI Jumping World Cup North American League Washington with one of only two double-clears in the class.
Fifteen riders will descend on Riyadh for the clash of champions in the €1.25 million Longines Global Champions playoff event.