However, the clash provided the 35-year-old with the opportunity to say goodbye to the Arsenal faithful, having helping Arsene Wenger's side win two league and three FA Cup titles during his six-year spell at the club.
“Personally, I wasn’t expecting such a warm and an amazing welcome from the Arsenal fans,” he told the club's official website.
“It shows how great the Arsenal fans are and that they don’t forget their former players. I was really touched and moved by their ovation and the fact that they were singing my name.
Pires believes Villarreal missed their opportunity to progress to the last four in the first leg encounter at El Madrigal, where Marcos Senna's blockbuster handed the Spaniard's the lead, only for Emmanuel Adebayor's overhead kick to equalise.
“We have some regrets from the first leg where we could have scored more goals and made a bigger difference,” he said.
“That’s where we missed the chance to go through. But Arsenal was too strong for us. Physically we responded, something we didn’t do in the first leg, but they managed to score more than us."
And the former Marseille man warned his former club that they should beware Barcelona, should both clubs reach the final in Rome.
"England always have the same clubs in the last four of the Champions League which shows that the way they are playing football is the best," he said.
"But they should watch out for Barcelona. They are the only ones left that will try to break the English domination.”
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