Denis has warned Celta they risk being sucked into the relegation battle if they don't shake themselves.
He snapped: "What you can't do is have two shots per hour. We are not aware that those below are winning and we have a margin, but it is not definitive. We have to win no matter what and we've wasted a great opportunity.
“If I'm honest, we have created, but not much. The game has gone from one side to another, we have not had control, we have not been forceful, we have not been aggressive as we normally are.
"We made very few fouls in the first half. Now in the second half, when we were better, I don't know why in the last ten minutes we started to pass short, play slowly and look for a draw.
"We had to go for the win. They were level on points and by winning today we would have taken a three-point margin from them. In the end we leave with a deserved defeat."
Denis added: "Others are playing well and it seems that we are not doing anything when it is not like that."