Champions League hopefuls Athletic Bilbao got their La Liga campaign off to a poor start as they were beaten 1-0 at Malaga on Saturday.
Liverpool loanee Luis Alberto scored the only goal of the game as he tapped home the rebound after Gorka Iraizoz had saved his penalty 10 minutes before half-time.
The hosts ended the game with nine men after Duda and Vitorino Antunes saw late red cards, but they held on as Iraizoz had a stunning stoppage time equaliser controversially ruled out for offside.
Athletic will be hoping for an immediate response when they host Napoli in the second leg of their Champions League qualifier at home on Wednesday with the tie locked at 1-1 from the first leg.
Valencia began their new era under owner Peter Lim with a 1-1 draw at Sevilla thanks to a late equaliser from Lucan Orban.
Sevilla, who are heavily fancied to take the fourth Champions League place this season, had gone in front a minute before half-time as debutant Aleix Vidal smashed home from close range.
However, Valencia responded after the break and despite having Rodrigo de Paul sent-off were level two minutes from time when Orban bundled the ball home from a corner.
Espanyol also rescued a draw at Almeria at the death as Sergio Garcia's effort in the 13th minute of stoppage time handed them a 1-1 draw at Almeria.
The game had been delayed by a floodlight failure after Fernando Soriano had fired Almeria into a 52nd minute lead.
And the Catalans made the most of the added time as Garcia's effort trickled into the far corner with virtually the last kick of the game to salvage a point.
Granada were the other winners of the opening day of the campaign as they game from behind to beat newly promoted Deportivo la Coruna at Nuevo Los Carmenes.
Ivan Cavaleiro had given the visitors the perfect start with a low drive that sneaked in at the near post.
But Granada responded after the break as Ruben Rochina levelled before Babin headed home the winner 13 minutes from time.