Los Che, who are 18th in the table, suffered a 3-0 loss to Atletico Madrid before the international break, while Rayo will enter the contest off the back of a 2-2 draw with Girona.
Match preview
Valencia have not played outside of Spain's top flight since 1987, but they are currently involved in a La Liga relegation battle heading into the final straight.
A hugely disappointing campaign has seen Los Che collect just 26 points from 26 matches, which has left them in 18th position in the table, one point behind 17th-placed Espanyol in the table.
Only basement side Elche (17) have lost more La Liga games than Valencia (14) this term, while they have only managed seven victories in Spain's top flight during the 2022-23 campaign.
Ruben Baraja's side suffered a 3-0 defeat to Atletico in their last game before the international break, but they have been victorious in each of their last two league matches at Mestalla, beating both Real Sociedad and Osasuna 1-0.
Valencia have found it difficult in their recent meetings with Rayo, though, failing to overcome the capital side since November 2018, while they lost 2-1 in the reverse match between the two sides earlier this season.
While Valencia are battling to stay in the league, Rayo are bidding to finish in the top six, with the capital side currently eighth in the table, five points behind sixth-placed Villarreal.
Andoni Iraola's side are actually winless in the league since the start of February, though, drawing four and losing two of their last six matches in Spain's top flight.
Rayo will enter this game off the back of a 2-2 draw with Girona, who twice came from behind to secure a share of the spoils in the contest at Estadio de Vallecas.
Los Franjirrojos finished 12th on their return to La Liga last season, and they are bidding to make it back-to-back campaigns at this level of football for the first time since 2016.
The team's recent struggles when it comes to winning matches have seen them slip down the table, but it has still been a hugely positive campaign for the club, who have picked up 16 points from their 13 away league games during the 2022-23 campaign.
Valencia La Liga form:
L
L
W
L
W
L
Rayo Vallecano La Liga form:
D
D
L
D
L
D
Team News
Valencia were missing four players through injury against Atletico last time out, and that will again be the case for Monday's fixture at Camp Nou.
Toni Lato, Gabriel Paulista, Marcos Andre and Jaume Domenech remain on the sidelines, but Los Che do not have any fresh concerns.
There are expected to be changes from the side that started against Atletico before the international break, with llaix Moriba, Samuel Lino, Andre Almeida and Edinson Cavani potentially all coming into the XI.
Rayo, meanwhile, will have Ivan Balliu back in their side on Monday night, with the 31-year-old serving the suspension that ruled him out of the contest with Girona last time out.
The capital outfit have no injury concerns heading into this match, meanwhile, so Balliu for Mario Hernandez could be the only change from the side that started against Girona.
Raul de Tomas is an option to start in the final third of the field, but Sergio Camello is again likely to be given the nod as the lone centre-forward.
Valencia possible starting lineup:
Mamardashvili; Foulquier, Comert, Ozkacar, Gaya; Moriba, Guillamon, Almeida; Lino, Cavani, Kluivert
Rayo Vallecano possible starting lineup:
Dimitrievski; Balliu, Lejeune, Catena, F Garcia; Valentin, Comesana; Palazon, Trejo, A Garcia; Camello
We say: Valencia 1-1 Rayo Vallecano
Valencia have picked up important wins in their last two La Liga matches on home soil, while Rayo have struggled for victories in recent weeks. The visitors have drawn nine league games this term, though, including four of their last six, and we can see another stalemate in Monday's contest at Mestalla.