A SECOND half comeback by Athletic Bilbao condemned Malaga to their seventh loss of the season.
Playing at La Rosaleda the home team had gone ahead through Juanmi in the 38th minute to keep Malaga happy going into the break.
But things were to change in the second half as first San Jose equalised before Portillo was sent off for a second booking with seven minutes to go.
The hosts could not hold on with Muniain knocking home the winner two minutes later.
Speaking after the match Malaga coach Bernd Schuster said: “We didn’t deseve to lose this match at all. We did enough to win tonight , but when we were down to 10 men for a while it was hard. We are very disappointed of course.”