The Gunners defeated Real Madrid home and away to reach the Champions League semifinals.
Villa told Marca: "I think they played a great game, they didn't allow Madrid to try that comeback.
"I think the key was the first leg. Yesterday it was very complicated, despite their history of comebacks. Arsenal had a significant advantage."
Barcelona, on the other hand, despite losing their second-leg at Borussia Dortmund, managed to reach the semifinals.
Villa added: "The feeling is very good.
"I'm very happy with how things are going, not only in terms of results, but also with the game and what they are expressing in each competition. As a Barça fan, you can't help but enjoy this season.
"A particular favorite? All the remaining teams are favourites. If they got this far, there's a reason."