The New Zealander and 'Max' were one of just four to go double-clear; Jessica Phoenix and Fluorescent Adolescent bound up the 4* leaderboard.
The US rider is closely followed by Phillip Dutton and Possante; Canada is represented in the CCI4*-S by Jessica Phoenix and Fluorescent Adolescent.
There were a pair of Canadians on the podium at the Florida Horse Park, with Sarah Wyssen and Peace Out Man taking 3rd spot.
Members of the iconic Musical Ride benefited from a two-day confidence- and skill-building workshop with eventer Jessica Phoenix.
Canada's Jessica Phoenix and Freedom GS finish 21st in elite company at the UBS-Cup CCIO4* at CHIO Aachen.
The US rider had led after dressage, but slipped to 4th after cross-country before bouncing back; Canadians won the 4*-S and the 2*-L.
The Aussie moved to the top of the leaderboard with both her rides ahead of Canada's Jessica Phoenix and Wabbit following Saturday's cross-country.
Germany’s Michael Jung and 'Chipmunk' won the 5*-L, while Canada's Jessica Phoenix and Freedom GS charged from 14th to 3rd in the 4*-S.
The small but mighty contingent of Canadians had a great cross-country day; Jessica Phoenix sits 13th with Fluorescent Adolescent in the CCI5*-L.
Boyd Martin and Tom McEwen take over second and third place in the CCI5*-L; Canada's Jessica Phoenix and Fluorescent Adolescent are 20th.