Real Madrid had gone behind in the game thanks to a goal from Iker Munain in the first half for the home side.
Bilbao had managed to keep the European champions at bay well, but that ended in the 64th minute.
Toni Kroos picked up the ball in midfield and picked out Gareth Bale on the right wing with a perfectly weighted chip.
The Welshman caught up with the ball and delivered a cross in to the box with his first touch.
Isco was waiting in front of goal, and headed the ball low in to the left side of the net.