Both sides are in the mix for a European finish in La Liga, but Aguirre has conceded that tonight's match will be difficult against the Yellow Submarine.
"Villarreal are coming back from Segunda and are having an excellent season," he told reporters at a press conference.
"They have great forwards, Gio (Giovani dos Santos) and [Ikechukwu] Uche. I know them because I've coached both of them. They are coming here to defend their place in Europe.
"We'll come out with the style that's in our DNA and try to make the fewest mistakes as possible. I've been a manager in Spain for 12 years and I have always relied on 42 points. We are 10 short and we can do it."
Espanyol are currently 10th in La Liga, while Villarreal sit sixth.