Potard had been called up to take on Butler with the Evolve MMA fighter having only recently defeated James Kouame in One FC 10: Champions & Warriors last month.
The Evolve MMA fighter had also just stepped into the cage moments after team-mate Mitch Chilson had suffered a humbling loss to Shannon Wiratchai in the previous contest.
The American, considered one of the top prospects in the light heavyweight division in the region, had earlier achieved three first-round victories under the One FC banner but the experienced Frenchman, who has five wins and three losses to his name, appeared unfazed by the 30-year-old's blossoming reputation.
Butler appeared discomforted by the size of his opponent and could not easily bring him down to the floor in order to execute his masterful ground game within the first round. Instead, Potard managed to reverse a hold towards the end of the first round as the fighters appeared evenly matched.
The bell struck for the first time in Butler's career and it was apparent that Potard could be the first opponent who could face Butler till the end.
Reenergised after the break, Butler launched a powerful left kick that thundered onto Potard's chest but the Free Fight Academy fighter maintained his composure and saw an opening that allowed him to bring the fight to a premature end.
Butler, to his credit, tried to retaliate but further blows to the head made him lose control, necessitating referee Yuji Shimada's intervention in order to bring an end to the fight and hand the American the first loss of his career.
Arnaud Lepont also rushed to the cage to celebrate with his compatriot whose record improves to 6-3-0 with the win.