The only rider to produce a clear round over the Frank Rothenberger-designed course, he edged Eve Jobs, who had just a single time fault.
It came down to a two-horse race between Hannah Rajotte/ Patronus and Ashley Arnoldt/Lestat OLD over Peter Holmes' course at tbird.
“I was coming here mostly just to go around" said the Canadian, who rode Emerson, about his first show back after the Tokyo Olympics.
A contentious eight-horse jump-off saw Vanessa Mannix (CAN) and Catinka 25 settle for second with Conor Swail (IRL) and Theo 160 third.
Excitement is mounting ahead of the 2021 fixture which kicks off at Riesenbeck International in Germany on Sept. 1.
The newlywed won the $15,000 CSI3* Maui Jim Winning Round 1.45m aboard her longtime mount, Goodwill VB.
In the four-horse jump-off in the 1.50m CSI3* class on Thursday, the Irishman stacked the odds by making up 50 per cent of the lineup.
After making the podium on three other occasions at the Summer Fort Classic, Mannix broke through with an impressive win.
The Frenchman topped the field of 35 at the Hubside Jumping de Valence in front of grandstands full of enthusiastic crowds.
As the border gradually reopens to non-citizens, it sees the welcome return of international competition to Thunderbird Show Park.