He then set up Alexis Sanchez two minutes later, and Barcelona looked set to win until Bilbao's Ander Herrera pounced on a loose ball to shoot just inside the post in the 90th.
Craig Fagan was sent through on goal and, after Boro keeper Brad Jones had swatted the ball away from him as he prepared to shoot, Manucho sent the loose ball across the face of goal.