The midfielder is remaining upbeat over his side's chances of qualification, despite losing at home on Tuesday night
The Liga outfit looked on course to be out of contention altogether after conceding two goals without reply in the first half, until Adil Rami's last minute strike and Zlatan Ibrahimovic's red card gave the home side a fighting chance.
"It's a bad result for us but we have hope. We knew they had quality up front and they showed that," Canales told reporters after the game.
"There is still a lot left in this tie and – even though we know it will be difficult – we will look to score early over there to give ourselves a chance."
Meanwhile, head coach Ernesto Valverde also spoke about the challenge his side overturning a first-leg defeat.
"We have to recognise that our opponent is a great team with great players and they have shown their strength," the 49-year old added.
"In the end we managed to score that goal and that gives us some hope but we know that the return [fixture] will be difficult."