Valencia coach Gary Neville called the referee "a joke" and "embarrassing" after his team were beaten 3-0 by Athletic Bilbao at Mestalla on Sunday afternoon.
The game seemed headed for a goalless draw, but Athletic scored three times in just seven minutes during the final quarter, with Sabin Merino, Iker Muniain and Aritz Aduriz on the scoresheet.
Valencia had earlier had the better chances of a tight game, with midfielder Andre Gomes and striker Alvaro Negredo having penalty claims ruled out, and referee Jesus Gil Manzano blowing for offside when Los Che had the ball in the net just after half-time.
The former Manchester United defender told his postmatch news conference that the refereeing had been one of the three reasons his side had lost the game.
"There were three factors," Neville said. "First of all I thought the referee was a joke. I've not blamed referees in every game, but some of the things he did were incredible. We know it's a difficult job, but I don't understand how we didn't have one of two penalties, one for Gomes, the other for handball [from Negredo's goal-bound header].
"I don't have a clue -- it was embarrassing they were not given. And he booked three of our players and I don't know how many fouls they had compared to us. Second we missed chances. Third we didn't react to conceding the goal."
Neville said that until Merino opened the scoring with less than 20 minutes remaining, a Valencia team who had won their previous four games in all competitions had been the better side.
"I thought we were better for 70 minutes," Neville said. "I thought it was a tight game. We looked confident, in control, Bilbao had problems with us. I was amazed we didn't go 1-0 or 2-0 up, I was amazed we didn't get a penalty. The goal shocked us and we tried to score again immediately, rather than trying to settle down.
"Maybe we got a little bit desperate after the first goal went in. That's my only criticism of our performance. We did not throw the towel in, it was more the desperation to try and get back into the game. It looks like a terrible defeat, which it is, but that wasn't a 3-0 loss."
Valencia soon face Athletic again in the Europa League last 16, with the first leg at San Mames on Thursday March 10. But Neville said his immediate focus was the upcoming La Liga games at Malaga on Wednesday night and at home to Atletico Madrid next Sunday.
"They [Athletic] know that they won't have a comfortable game in two weeks, although my focus now is not on two weeks, it's Malaga and how we respond," Neville said. "The headlines will obviously be negative, but watch the game and think about how it could have been for us.
"Valencia fans will be angry, I'm angry, we'll go home and think we should have been 2-0 or 3-0 up. Malaga is everything for us now, Atletico is everything for us, before we play Bilbao, we have two very big games this week and we have to respond quickly."