The Yellow Submarine conceded a first-half penalty on their own patch and Marcelino believes that his side are being targeted by referees this season.
"It was easy to give fouls against us here," he told reporters at a press conference.
"If they gave that as a penalty today then there should be 20 in every match. We're not having any luck with decisions."
Villarreal remain in seventh position in La Liga with seven games remaining.