Real Sociedad coach Imanol Alguacil was left frustrated after their 1-1 draw with Alaves.
A 96th minute equaliser from Martin Zubimendi earned La Real the point after the first-half dismissal of Alex Remiro.
Imanol said: "I'm leaving like other times when we deserved the three points and we didn't get them, even having played with one less which speaks highly of my players. We entered the locker room with that feeling that, if anyone deserved to win the game, it was us.
"I think the only shot they took was the penalty and we had more options.
"Thinking about how we had to position ourselves to defend, also in attack to be able to have scoring situations. That's what I did, I started thinking about what we could do. They are game events, this has not been normal, because Álex has always conveyed a lot of confidence in these types of actions, in which he has a very good reading.
"It was a mistake, period."