Former Cardiff City striker Javi Guerra struck for Malaga in their 1-1 draw at Athletic Bilbao.
Guerra's strike came just eight minutes after defender Mikel San Jose had given Bilbao the lead.
It was the second time the teams had drawn against each other in a week, following on from their stalemate in the Copa del Rey at La Rosaleda.
The teams will return to San Mames on Thursday, when there must be a winner as both sides target a place in the last four of Spain's cup competition.
