Barcelona have exacted revenge for their Spanish Super Cup thrashing as Luis Suarez's second-half volley secured a nervy 1-0 win over Athletic Bilbao on the opening day of the La Liga season.
A golden opportunity to break the deadlock arrived on the half-hour mark when Suarez was adjudged to have been tripped inside the area by Gorka Elustondo, but Messi's spot kick was saved superbly by Gorka Iraizoz.
Barca had another great opportunity 10 minutes before the whistle when Suarez's effort was stopped by Iraizoz, and Elustondo blocked another strike from the Uruguayan as the sides headed into the break goalless.
The champions finally took the lead with the first chance of the second half, when Jordi Alba hooked in a cross from the left and Suarez found himself completely unmarked to volley home from close range.
They nearly doubled their lead just six minutes later when substitute Sergi Roberto ended a superb passing move with a strike which smashed the top of the crossbar.
The home side rallied late on and could have equalised when Ibai Gomez wasted a huge opportunity by firing over the bar from inside the Barca box, but the damage had already been done as the visitors held on for victory.