Quique Setien's honeymoon period lasted less than a fortnight as he tasted his first Barcelona defeat in his second La Liga game in charge after a 2-0 loss to Valencia.
A Jordi Alba own goal and Maxi Gomez's strike at Mestalla on Saturday raised early doubts about Setien's appointment and gave Real Madrid the chance to move three points clear at the top of the table when they visit Real Valladolid on Sunday.
Sevilla jumped into third, above Atletico Madrid and five points behind the top two, after they beat Granada 2-0.
Barcelona had most of the ball but Valencia had the best chances as Gomez missed a penalty and also hit the crossbar in the first half. Gabriel Paulista saw a third goal ruled out late on.
While performances under previous coach Ernesto Valverde were stodgy and familiar failings went unresolved, he left a side in first place.
Setien promised a new style but few will cheer a team that loses. Despite dominating possession, Barcelona did little with it and as Valencia grew in confidence, they ceded control too.
"There are things they have not understood or maybe we have not have explained ourselves well," Setien said afterwards.
"In the first half, quite frankly, we were bad."
"There were some good things but we have to improve."
- Valencia dangerous -
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