Gonzalo Escalante, Sergi Enrich and Kike Garcia piled misery on Real Madrid, who are sixth, in an anaemic display in the Basque country.
The Mestalla, famous for its imposing North Stand, is the home of Valencia and the oldest among the stadiums that are currently hosting La Liga matches.
Atletico Madrid may be looking at its best chance to end an eight-year winless streak against Barcelona in the Spanish league.
While women hold high offices at Real Madrid, Real Sociedad and Leganes, Eibar are the only club in Spain where over half of the management positions are occupied by women.
Ousmane Dembele was left out of the squad for Barca's 4-3 defeat by Real Betis last Sunday after failing to turn up to training three days earlier.
The Croatian had already been ruled out of his country's winner-takes-all game against England on Sunday in the new competition and was sent back to Barcelona, where he underwent tests on Saturday
That message was made clear in bold, black type in the Herald on Thursday, urging fans; "Let's do it together. For the Game, For the Fans. For Miami".
Santiago Solari has led the team to four wins in four games since replacing Julen Lopetegui at the helm of the European champions two weeks ago.
Ousmane Dembele was not included in Barcelona's squad for defeat to Real Betis after not turning up to training and reportedly not informing the club of his whereabouts for 90 minutes.
The win over Celta Vigo saw Real Madrid climb to sixth on 20 points from 12 matches in a jam-packed La Liga table closing the gap on Barcelona on 24 points.
Barcelona fell to a first home defeat in any competition for more than two years when they were beaten 4-3 by Real Betis at the Nou Camp on Sunday despite Lionel Messi returning from injury.
Atletico Madrid twice came from behind to pull off a thrilling 3-2 win at home to Athletic Bilbao on Saturday.
Messi has been training in the last week and travelled with the team to Tuesday's Champions League game against Inter Milan but did not make the bench for the 1-1 draw.
The coach has endured a nightmare year after being sacked by Spain on the eve of the World Cup after agreeing to take the Real Madrid job.
The league's idea to play games in the US to promote its brand has been supported by many but has also been met by criticism from soccer officials and some fans and clubs in Spain.
Barcelona gained from a draw by third-place Atletico Madrid on Saturday, draw by Sevilla and loss by fourth-place Alaves on Sunday.
Real Madrid ended their long wait for a La Liga victory by beating Real Valladolid 2-0 on Saturday.
David Beckham does not think Real Madrid is going through anything as significant as a "crisis" and is confident his former club will soon emerge from their current run of poor form.
Gareth Bale, Real's record signing, has been in the firing line this week for a limp display in the thrashing at the Nou Camp.
For the rest of the world, February 14 might signify the date when couples declare their love for each other but for the good folk of Leganes, it signifies the day Estadio Municipal de Butarque was opened back in 1998.
The league and its US partners on Thursday began asking fans to sign an online petition to show their support for the planned Barcelona-Girona game near Miami in January.
Former player Santiago Solari, coach of Madrid B, was in charge of practice on Tuesday, but the club was in a hurry to find a replacement.
Real Madrid are ninth in La Liga after a 5-1 drubbing by Barcelona on Sunday.
The club says Santiago Solari, coach of Real Madrid B, will be in charge until a replacement for Julen Lopetegui was hired.
Real Madrid coach Julen Lopetegui is likely to pay for the team’s poor start to the season, but Spanish media have also criticised the club’s players and Gareth Bale, in particular.