Three teams will be relegated and Real Valladolid are currently in the danger zone, in 18th place, a point behind Celta Vigo and Almeria who have 40, while Valencia, Getafe and Cadiz all have 41 and are still sweating on their survival.
All six teams know if they win on Sunday, they will survive - with Getafe's visit to Valladolid the only match featuring two of the six and potentially the key fixture.
If Getafe win at Pucela, they can save themselves and four other teams by consigning Valladolid, whose president is Brazil great Ronaldo, to relegation.
The battle might have been tighter still, had Valencia not found a late goal to draw last weekend at Espanyol, consigning the Catalan side to relegation.
If teams are level on points at the end of the season, their head-to-head record is the first tie-breaker, with goal difference second.
Should more than two teams be tied, a mini-table based on their head-to-head scores will decide their placings.
Cadiz, 13th, are the highest side still in danger, and a single point on the road at relegated Elche would ensure their survival, with the same true for Getafe at Valladolid and Valencia, who visit Real Betis.
Los Che have had a miserable season, with the six-time champions set for potentially their lowest finish since being promoted to the top flight in 1988.
"We have to focus on the game and on ourselves, and go to Seville to play a good game to seal survival," said Valencia coach Ruben Baraja.
Almeria travel to relegated Espanyol, knowing a draw will be enough to save them, as they have a winning head-to-head record against Getafe.
Celta Vigo, 17th, are winless in six league games and have sustained seven defeats across their last nine matches.
The Galicians face champions Barcelona, whom they hope are relaxed and with their minds on the summer break after wrapping up the title and having an emotional goodbye to Camp Nou last weekend.
Even a draw against Barcelona is not enough to guarantee survival - to do that, Celta need a victory.
Celta announced on Wednesday they will open a stand that has been closed for works all season as they look to pack Balaidos and turn their fortunes around.
"The one positive is that we finish the season at home and it's up to us to earn survival," said coach Carlos Carvalhal (57) after last weekend's costly 1-0 defeat by Cadiz.
While Valladolid also crave three points, they could even survive if they draw against Getafe, should Almeria lose and Celta take at least one point.
There will be twists and turns along the way as La Liga's relegation battle is fought to the bitter end.
Player to watch: Cyle Larin (28)
The Canadian forward has hit the ground running at Real Valladolid and their best hopes of survival lie with him in the clash against Getafe. He has netted eight goals in 18 appearances since arriving in January.
Key stats:
14 - Rayo Vallecano's Alejandro Catena and Espanyol's Oscar Gil are tied for the most yellow cards
121 - Real Madrid's Vinicius Junior has been fouled the most in LaLiga
193 - Almeria's Rodrigo Ely (29) has made more clearances than any other player
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