The team dominated Villa at Wembley, with goals from Ismaila Sarr and Ebere Eze contributing to a 3-0 win.
Guehi credited the team's success to their unity and spirit throughout the game.
"It was a tough game against a strong opponent, and in matches like these, it's the small moments that make all the difference," he said.
"Today, we showed that we can come together and support each other, which is crucial in these types of matches," he added.
Guehi also thanked the fans for their unwavering support, saying that their noise and enthusiasm were the same whether they played at home or away.
He praised manager Oliver Glasner and goalkeeper Dean Henderson for their contributions to the team's success.
"Dean is incredibly vocal and helps us in big moments like today," Guehi said.
"Oliver is top-notch and his staff do an excellent job of analyzing and preparing us for each game," he added.