After registering two assists on his LaLiga debut as a substitute on the weekend, Anthony Gordon was heavily involved from the start here as Barcelona looked to utilise his pace and direct running against an Athletic defence that were quite static.
Los Leones were compact when defending, but Barca began to exert their authority. Raphinha almost latched onto Fermin Lopez’s pinpoint pass before Lamine Yamal’s curling effort saw Unai Simon go full stretch to his right in order to make the save.
Joan Garcia came to the hosts’ rescue after his defence was split open, rushing from his goal to clear, before Raphinha headed against the post with Simon beaten.
As the half hour approached, Pedri looked to have finally given the Catalan giants the lead, but an offside flag for Lamine from earlier in the move saw the game remain goalless.
Peio Canales and Oihan Sancet caught the eye for Athletic, but the visitors were powerless to stop Pedri playing in Raphinha in the 37th minute, as the Brazilian rounded Simon and passed the ball into an empty net.
Barca pushed for a second before the break, but Simon then pulled off a world-class save to deny Lamine.
Gordon wasted a great chance right at the start of the second half, firing over when well placed, before Lamine smashed a shot against the crossbar as Athletic’s defence just stood and watched.
Despite the best efforts of the Williams brothers to make inroads into Barca’s half, they were hemmed in as the hour mark approached, and in fact, both were then replaced by Edin Terzic. Simon was equal to Fermin’s volley before the biggest cheer of the night for Rodri as he made his debut.
As the game eased towards its conclusion, Sancet fired a daisy cutter against García’s right-hand post, with Barca beginning to look vulnerable when Athletic pressed.
With less than 10 minutes left, however, Fermin tapped home a second after Aymeric Laporte’s mistake to cap a fine personal performance.
The win sees Barca top the league table after two games, whilst Athletic, beaten for the seventh time in the last eight away matches, find themselves second from bottom.