While the home side are two points clear of the danger zone, 19th-placed Espanyol are three points adrift of safety and could be relegated this weekend.
Match preview
After picking up seven points from three games, Valencia had the chance to guarantee their safety when they made the trip to Mallorca in midweek.
Their top-flight status would have been secured with a victory, but they returned to the mainland empty-handed after falling to a narrow 1-0 defeat.
Valencia academy graduate Lee Kang-in scored the winner for Mallorca in October's reverse fixture, and he haunted his former club once again, producing the cross for Vedat Muriqi to head home the winning goal in Thursday's contest.
Ruben Baraja's side will now return to Mestalla, where there will be a partial stadium closure following the racist abuse that Real Madrid's Vinicius Jr in their most recent home game, and the hosts will be hoping to secure survival on Sunday rather than sending their relegation battle to their final game of the season against Real Betis.
Having lost just one of their 13 home La Liga games against Espanyol (W10, D2), Valencia will be hopeful of claiming a positive result on Sunday.
After claiming a 2-1 win over Rayo Vallecano last weekend, Espanyol entered Wednesday's home game against Atletico Madrid with hopes of recording consecutive victories, but those aspirations were quashed inside 46 minutes, as Diego Simeone's side established a seemingly insurmountable three-goal lead.
However, Espanyol showed great fighting spirit to mount a remarkable comeback thanks to goals from Cesar Montes, Joselu and Vinicius Souza.
In normal circumstances, picking up a point after trailing by three goals would have been considered a successful result, but the draw leaves Espanyol hovering over the trap door with three points separating them from safety.
If the Periquitos lose to Valencia, they will be relegated if two of Getafe, Cadiz and Real Valladolid avoid defeat, and a draw would prove insufficient if both Getafe and Cadiz clinch maximum points.
Luis Garcia will be imploring his side to focus on themselves, as the visitors look to claim consecutive away victories in La Liga for the first time since May 2018.
Valencia La Liga form:
W
L
D
W
W
L
Espanyol La Liga form:
L
W
L
L
W
D
Team News
Baraja should have the majority of his Valencia squad available to him, although he is still unable to call upon Marcos Andre.
After missing the trip to Mallorca through suspension, Eray Comert and Yunus Musah will return to the matchday squad, but the pair may have to settle for places on the bench.
Justin Kluivert and Edinson Cavani could return to the starting lineup after dropping out of the side for Thursday's defeat.
As for Espanyol, Jose Gragera remains a doubt for Sunday's contest after missing the club's last six matches with an injury issue.
After featuring as substitutes against Atletico Madrid, Vinicius and Martin Braithwaite could be brought into the starting XI.
Joselu has top scored for Espanyol this season, and he will be looking to add to the 16 goals that he has scored this season.
Valencia possible starting lineup:
Mamardashvili; Correia, Diakhaby, Paulista, Gaya; Guerra, Nico; Lopez, Almeida, Kluivert; Cavani
Espanyol possible starting lineup:
Pacheco; Gil, Montes, Calero, Cabrera, Olivan; Melamed, Vinicius, Darder; Braithwaite, Joselu