Barcelona claim a third away win in a row after an entertaining game. Athletic briefly looked like causing Barca further grief as they grabbed an early lead, but Barca soon turned things around with Messi the star of the show.
Muniain gave Athletic hope at the end but hope was all it turned out to be.
Barca rise to third in La Liga, five points behind Real Madrid and seven behind leaders Atletico Madrid who have two games in hand.
It’ll be hard for Koeman’s team but there’s no reason they can’t budge their way back into the title discussion if they keep this form up.
Athletic stay ninth. They’ve not had a bad first outing under Marcelino.
Barca now travel to seventh-placed Granada for their next match while Athletic host title contenders Atletico.
