Amorebieta was shown a red card by referee Raul Orozco for stamping on Paulo Guerrero's knee just shy of the half-hour mark in Valparaiso on Thursday.
The left-back's careless dismissal ultimately led to Venezuela's demise as Claudio Pizarro scored the winning goal with 18 minutes remaining to blow Group C wide open.
Speaking to reporters post-match, Amorebieta said: "I did not intend to stand on him but will not criticise the referee because he decides.
"I can only take the blame because the red card changed the game."
Thursday's result leaves the group up for grabs, with Peru, Brazil, Venezuela and Colombia all level on three points with one match remaining.
Venezuela face eight-time champions Brazil in their final group fixture on Sunday but coach Noel Sanvicente is undaunted by the task ahead, having already stunned Colombia in their tournament opener.
"We will put in an excellent performance to qualify. In this Copa America we beat Colombia for the first time in competition, perhaps we can beat Brazil for the first time," Sanvicente said afterwards.
"The Copa is very even and anyone can beat anyone. In the group we are all the same and it will be like starting from scratch.
"We have to go out with the mentality that we can win, but we'll keep playing our style and our strengths."