Santiago Solari faced up to his first defeat in charge of Real Madrid and admitted: "We didn't perform at all well."
The Argentinian had made the best start by any boss in Real's history with four successive victories after taking over on an interim basis and he was given a permanent deal running until 2021 during the international break.
But any notion of extending his honeymoon period was emphatically closed as goals from Gonzalo Escalante, Sergi Enrich and Kike gave Eibar a first ever win over the Spanish giants.
Solari told Real's official website: "Blaming or picking out individuals doesn't get you anywhere.
"We weren't good enough, we know we have to correct things, we didn't perform at all well and we have to rethink a few elements.
"We came in off the back of four wins, there were positive aspects to be taken, we did some things well and we have to focus on those.
"Obviously the dressing room is not jumping for joy after a defeat. Recent games have given us reason to be optimistic and positive."
When it was goalless, Gareth Bale had his strike chalked off because he was offside while Marco Asensio chipped over Eibar goalkeeper Asier Riesgo, only for Jose Angel to clear off the line.
But the hosts never looked back once they got their noses in front, leaving Solari lamenting his side's quality but not their attitude.
He added: "Eibar played with real heart and that was clear for all to see. They played extremely well and we couldn't match them.
"We had chances to score but failed to do so.
"I don't think it was a problem with attitude. The players worked hard and gave it all they had. Not one of them has given it anything less than 100 per cent.
"We lost little battles which end up taking their toll. It's a very tough place to come and we weren't able to get the better of them."
Eibar delivered on boss Jose Luis Mendilibar's pre-match promise to take the game to Real.
He said in quotes published by Marca: "We played very well, generating chances from the beginning. Against Madrid you always have the fear of conceding goals but they didn't have many chances.
"We could have scored more goals.
"It's rare that Madrid do not score goals, but we played a very complete match, attacking and defending very well. This victory will be very good for us to continue believing in what we do."
