Three points for Alaves could see them go four points clear of the drop zone in La Liga, while defeat for Eibar would all but relegate the hosts.
Bottom-of-the-league Eibar are in the midst of one of their worst runs so far season, with Jose Luis Mendilibar's side having gone winless since early January.
Mathematically though, Los Armeros are still keeping their heads above water and three points against local rivals Alaves would go a long way in reigniting the side's survival bid.
Last time out in the league, Eibar were beaten 1-0 by Real Sociedad, but the scoreline did not tell the full story, with Mendilibar's men giving a good account of themselves, registering more possession (54%) and more shots on target (5) than La Real.
Eibar are currently 20th in the standings, cast adrift at the foot of the table and seven points away from safety.
The team have lost five of their last six games, but if there was ever an opportunity for one last hurrah, this weekend is it.
While Eibar have consistently shown faith in Mendilibar, Alaves opted, not for the first time this year, to roll the managerial dice, bringing in their third manager of the campaign - Calleja.
Calleja's impact at El Glorioso so far has been nothing short of miraculous, with the new boss collecting eight points from his first four games.
Last time out, against Valencia, Calleja's side drew 1-1, with John Guidetti bagging a late goal in what was a dramatic last ten minutes of the game.
With Valencia equalizing in the last minute of the game, El Glorioso came close to making off with all three points at Mestalla.
Regardless of that specific result, Alaves have been playing with a newfound resilience under the stewardship of Calleja, and three points this weekend could all but secure the team's La Liga credentials in this dramatic relegation dog fight.
Mendilibar will be without the experienced Alejandro Pozo for this tie, with the defender currently out with a hamstring injury.
Another absentee for Los Armeros is Pedro Bigas, who is out with a muscular injury.
The big absentee for Alaves ahead of this tie is Ruben Duarte, who is currently out with a foot injury.
Eibar possible starting lineup:
Dmitrovic; Correa, Oliveira, Arbilla, Angel; Leon, Diop, Recio, Atienza, Gil; Kike
Alaves possible starting lineup:
Pacheco; Navarro, Laguardia, Lejeune, Aguirregabiria; Jota, Pina, Battaglia, Edgar Mendez; Perez, Joselu
We say: Eibar 0-2 Alaves
We would expect Eibar to come out swinging in this tie, given what is at stake, but Alaves are the in-form team here and we think they will be able to put Eibar to the sword.