Barca began in typically dominant style, but despite their monopolisation of possession, it took them until 23 minutes to find the opener from a corner. Fabregas met the delivery with a strike at goal which was saved, but Iraizoz could only palm the ball out into the path of Gerard Pique, who slotted Barca into the lead.
Athletic Bilbao had done well to hold on until that point, and they appeared to hold little hope of cancelling out the opener - just two minutes later, Xavi chipped a long pass to Lionel Messi, allowed a criminal amount of space by the Bilbao centre-backs, and rounded Iraizoz to slot home. Fernando Amorabieta attempted to clear the ball, but only diverted it into the roof of his own net, but the goal was awarded to Messi regardless. Astonishingly, it was Xavi's first assist for Messi for almost 19 months.
With Bilbao wobbling, Barcelona effectively made it game over just before half-time, Cesc Fabregas unmarked on the edge of the area to thread a fine pass through to Adriano, who finished past Iraizoz's near post. Like the previous goal, it was a combination of ruthless precision passing from Barcelona, and suicidal defending from Bilbao.
After the break, Barcelona continued to dominate and press, and Cesc Fabregas made it four when he picked the ball up on the edge of the area and smashed home at the near post. Bilbao pulled one back immediately afterwards as Ibai Gomez collected a long pass and slotted underneath Victor Valdes.
Barcelona, however, were not to be outdone, and restored the gloss to the scoreline with a second from Lionel Messi, collecting a loose ball in the area before stepping inside the Bilbao defence and lashing an unstoppable shot into the top corner from 12 yards out.
The result was a deserved one for both Barcelona, who were typically brilliant, and Bilbao, who never looked in the game from the start and were guilty of some dreadful defending around their own penalty area. Whether the Athletic team of last year is gone forever remains to be seen, but the regression under Marcelo Bielsa is plain to see, and can hardly be blamed solely on the departure of Javi Martinez. At this rate, more will follow him.