Scott and Ursula XII pulled off a memorable win at the Longines Global Champions Tour Grand Prix in Mexico.
Eight riders made it through to the jump off but Scott and Ursula beat second-placed Daniel Deusser by nearly two seconds.
The win makes Scott the first rider to qualify for new Longines Global Champions Super Grand Prix at the GC Prague Play Offs in December.
Scott said: “I’m ecstatic about this win. Ursula is 17 and this win means a lot to us all.
“This ring was fantastic for Ursula as I could really play to her strength, which is her stride but it was still a very competitive jump-off and we did our best.”
“I definitely didn’t think I’d won until Eric Lamaze and Gerco Schroder had been, because they’re so fast. I knew it wasn’t over till the last one went in.”
On qualifying for Prague, Scott added: ”I’m delighted to be in the new Super Grand Prix.
“It’s a fantastic competition for us riders to have and to aim for. I think it’s going to be really exciting in Prague, a totally new concept and the first time they go indoors.”