Rayo Vallecano president Martin Presa has accused Villarreal of not competing after their 2-0 defeat at Sporting Gijon relegated the Madrid club.
Villarreal coach Marcelino had admitted in the build-up to the final day of the season that his affiliation with Sporting - starting his career as a player at the Asturian club before returning as coach in 2003 - made the tie "awkward".
Goals from Jony and Sergio Alvarez saw off Villarreal at El Molinon, leaving Rayo to lick their wounds, despite a 3-1 win over rock-bottom Levante.
But Presa was quick to point the finger of blame after the game, stating that Villarreal had not put sufficient effort into their fixture.
"Villarreal didn't compete in terms of their line-up, their substitutions or in their formation," Presa is quoted as saying by AS.
"From the first minute it was clear to see it was not a game of football. Out of respect in other years we have fought to the death in the final game.
"Villarreal didn't prepare at all. It's my opinion, a side that didn't prepare at all, who didn't shoot on goal or anything.
"You can win and you can lose but you have to compete."
Presa is determined to restore Rayo back to La Liga at the first time of asking and hopes highly rated coach Paco Jemez will stay on to see out the job.
"I am the primary person who is responsible for the relegation," Presa added. "I congratulate Sporting.
"For our fans, and I am the first one, we are going to take the side back into Primera Division.
"If Paco wants to stay on, he will, and we will start preparing the team from tomorrow for next season."