Fausti starred in a historic showdown against Grandmaster and Argentine Champion Sandro Mareco in a six-game rapid match held at the Dow Center in Bahía Blanca, Argentina, on November 15 and 16, 2025. The event, called the “Challenge Match,” was played at a time control of 20 minutes per player with a 10-second increment per move. After an even first day ending 1.5–1.5, Oro and Mareco entered the decisive Sunday tied. Fausti steadily grew in confidence and level with each game and ultimately won the match 3.5–2.5 without losing a single game. The result reaffirmed his upward trajectory following his impressive performances at international events such as the World Cup in Goa.