The Frenchman - who initially joined on loan last term, helping Villarreal to win promotion before signing permanently - scored in the 3-0 win over Osasuna as his side's perfect start to the Liga campaign continued.
They will face their biggest challenge yet when Real Madrid visit El Madrigal on Saturday, with Gareth Bale, the world's most expensive player, set to make his debut.
But 28-year-old Perbet, who left Belgian Pro League side Mons to try his luck in Spanish football, is relishing the prospect.
"This match, the most important of my career so far, does not stress me," he told L'Equipe. "I have somehow never been stressed for football.
"When I signed, my family and my friends told me about Real and Barca, but that's all. If we lose, it makes sense. There is no pressure to have and we will try to annoy them as much as possible in front of our fans."
Real, like their hosts on Saturday, have won their opening three matches and Welsh winger Bale will play some part, manager Carlo Ancelotti has confirmed.
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