BARCELONA (Reuters) - La Liga champions Barcelona were stunned by a rampant Celta Vigo attack as they lost 4-3 in a chaotic encounter on Sunday.
Barca had the chance to go top of the table after Real Madrid drew 1-1 at home to minnows Eibar but instead let in four goals at coach Luis Enrique's former side and slumped to their second defeat of the season.
Atletico Madrid go top of La Liga on 15 points, leading Real on goal difference, while Barca are fourth on 13, one point behind Sevilla in third.
Luis Enrique heavily rotated his side after the hard-fought 2-1 win at Borussia Moenchengladbach in the Champions League on Wednesday and his side paid dearly for the changes, falling behind to Pione Sisto's low strike in the 22nd minute.
Iago Aspas finished off a quick counter to double the home side's advantage in the 31st and two minutes later Barca were hit again, Jeremy Mathieu bundling into his own net.
Andres Iniesta came on at the start of the second half to mark his 600th appearance for Barca and nearly engineered a dramatic turnaround, assisting Gerard Pique's headed goal and helping to win a penalty which Neymar coolly converted.
Barca were quickly on the back foot again following an embarrassing error by goalkeeper Marc-Andre ter Stegen, who kicked the ball against Pablo Hernandez and watched it go straight into the net.
Pique reduced the deficit to a single goal in the 87th minute but could not avert the damage done by Barca's shaky defence.
Earlier on Sunday, Fran Rico stunned the Santiago Bernabeu Stadium by heading Eibar into the lead in the sixth minute, scoring the side's first goal against Real in La Liga.
Gareth Bale headed home a Cristiano Ronaldo cross to level in the 17th minute and score his 50th La Liga goal but could not prevent a fourth straight draw for the European champions in all competitions.
"We did not play in the first half and our opponents did. The second half was much better, which is something we've been saying too much lately," said Real coach Zinedine Zidane.
Antoine Griezmann made amends for missing a second penalty in as many games by hitting the opening goal for Atletico and Kevin Gameiro sealed the points with a close-range finish at the death, while captain Gabi also had a spot kick repelled by Valencia's penalty-saving expert.