Los Che recorded a 5-1 win over Getafe last Sunday to move into 10th spot in the table, while Rayo will enter the contest off the back of a 2-1 defeat at Osasuna.
Match preview
Rayo finished 12th in La Liga last season on their return to the top flight, and the capital side are bidding to make it successive campaigns at this level of football for the first time since 2015-16.
Andoni Iraola's side started their season impressively, drawing at Barcelona on the opening weekend before recording a 2-0 victory over Espanyol to make it four points from two matches.
Rayo have now lost their last two, though, suffering a 2-0 defeat at home to Mallorca at the end of August before starting September with a 2-1 loss at Osasuna.
A total of four points has left them in 14th position in the table, and they will now take on a Valencia side that have only won one of the last seven top-flight meetings between the two sides.
Both matches last term finished in 1-1 draws, while Valencia have not actually overcome Los Franjirrojos away from home in Spain's top flight since May 2013.
Valencia, as mentioned, will enter this game off the back of a morale-boosting result against Getafe, recording a 5-1 victory at Mestalla to post their second win of the campaign.
Toni Lato, Samuel Lino, Samu Castillejo, Nico Gonzalez and Hugo Duro were all on the scoresheet last time out, with the result following back-to-back 1-0 losses to Athletic Bilbao and Atletico Madrid.
A record of six points from four matches has left Gennaro Gattuso's side in 10th spot in the table, and they will now be looking for two more wins against Rayo and Celta Vigo ahead of the September international break.
Valencia finished ninth in La Liga last term but will be hoping to push closer to the European spots this term; they are some way from the side that finished fourth in back-to-back campaigns in 2017-18 and 2018-19, though, so it will be tough to challenge the top six.
Los Che, as mentioned, have found it difficult to beat Rayo in recent years, but they have lost just once to the capital side away from home since March 2014.
Rayo Vallecano La Liga form:
Valencia La Liga form:
Team News
Rayo were again missing Diego Lopez and Andres Martin through injury against Osasuna, and the pair are likely to remain on the sidelines for this contest.
Head coach Iraola is expected to resist the temptation to shuffle his pack for this match, but there could be two changes in the final third, with Isi Palazon and Radamel Falcao potentially coming into the side.
Palazon could replace Salvi in the starting XI, while Falcao might be preferred to Sergio Camello at centre-forward, with Alvaro Garcia again playing off the left for the home side.
As for Valencia, Jose Gaya is available again following a suspension, but Lato is likely to keep his spot at left-back following a strong display last time out.
Ilaix Moriba was sent off against Getafe and will therefore miss out here, while Mouctar Diakhaby and Marcos Andre will be absent through injury.
Duro is likely to take Andre's position in the final third of the field, while Cristhian Mosquera is set to replace Diakhaby, but it could otherwise be the same side that took to the field for the first whistle on September 4.
Rayo Vallecano possible starting lineup:
Dimitrievski; Balliu, Lejeune, Catena, F Garcia; Ciss, Valentin; Palazon, Trejo, A Garcia; Falcao
Valencia possible starting lineup:
Mamardashvili; Correia, Comert, Mosquera, Lato; Musah, Guillamon, Gonzalez; Castillejo, Duro, Lino
We say: Rayo Vallecano 1-1 Valencia
Five of the last seven La Liga meetings between these two sides have finished level, and we are backing another draw here. Valencia will be full of confidence due to their strong win last time out, but we believe that Rayo have enough quality to secure a point in front of their own supporters.