Lionel Messi scored a stunning late free kick as Barcelona came from behind to beat Alaves and maintain their unbeaten start to LaLiga.
The visitors were defending well after John Guidetti's fortuitous opener had put them ahead but they could not hang on as Luis Suarez levelled before Messi curled home a set piece to secure an unconvincing 2-1 win.
As Barcelona's forwards failed to fire, Alaves threatened so often on the counter-attack and it was no surprise that their goal came from such a move in the 23rd minute.
Guidetti slipped as he took his shot, which deflected off his standing foot to beat Marc-Andre ter Stegen and stun the Nou Camp.
Barcelona's club-record signing Philippe Coutinho made his full debut since joining from Liverpool but he was ineffectual before being replaced.
Lucas Digne was handed a rare league start and the full-back had the game's first decent chance, dragging a low shot wide from the edge of the box.
The hosts were enjoying plenty of possession although Ibai should have done better with a rare opportunity to put Alaves ahead as they broke on the counter-attack.
The visitors would go one better soon after as another pacey counter ended with Guidetti scoring his first goal for the club since his loan move from Celta Vigo, slipping at the key moment but still managing to convert.
Ter Stegen had to be at his best moments later to prevent Barcelona falling even further behind as he dived to tip Ruben Sobrino's header away.
The forward was proving a handful for the Barca defence and he raced away on the half-hour mark only to finish with a tame effort straight at ter Stegen.
Coutinho was involved in almost every attack and he came close to equalising only for his strike from the edge of the box to deflect behind for a corner.
Alaves goalkeeper Fernando Pacheco was alive to push an Ivan Rakitic flick-header behind as the midfielder got on the end of a Messi free-kick.
Messi's next free-kick was a direct effort and Pacheco was again able to keep out his effort with a marvellous stop.
Valverde wasted little time after the interval to introduce full-backs Sergi Roberto and Jordi Alba from the bench as the ineffectual pair of Digne and Nelson Semedo made way.
Barcelona's attacking talent just could not click and Alaves passed up another good chance to double their lead as Ruben Duarte saw his shot blocked following good work from Guidetti.
Valverde's final change saw Coutinho come off after a disappointing full debut moments before Suarez was kept out by Pacheco following a superb Messi pass.
Paulinho was the next to come close to an equaliser, latching onto a Gerard Pique flick to draw another stop out of the impressive Alaves goalkeeper.
But there was nothing he could do to keep out Suarez, who had been relatively quiet, as the Uruguay international turned home Andres Iniesta's cross at the back-post with 18 minutes remaining
Messi, as he so often does, then took centre-stage - curling home a perfect 84th-minute free-kick which Pacheco could not get near as Barcelona re-established their 11-point lead over Atletico Madrid.