Los Blancos are top of the La Liga table, five points ahead of second-placed Girona, while Rayo's poor form has seen them drop to 14th, seven points clear of the relegation zone.
Match preview
Rayo have not been victorious in Spain's top flight since the start of January, losing four of their last five matches in the league, including their last three against Atletico Madrid, Sevilla and Mallorca, all 2-1.
Inigo Perez has been appointed as the capital outfit's new head coach, with Francisco losing his job due to the team's poor run of form, and the 36-year-old will be tasked with moving the team back up the division.
Rayo's poor form has seen them drop into 14th position, with a record of five wins, nine draws and 10 defeats from 24 matches giving them just 24 points.
It is not quite time to hit the panic button, though, as the capital outfit are still seven points ahead of 18th-placed Cadiz and sit just three points behind Alaves in 12th.
Rayo, who finished 11th in Spain's top flight last season, have actually only lost one of their last three league games against Real Madrid and recorded a 3-2 victory in the corresponding fixture last term.
Real Madrid, meanwhile, will enter this match off the back of a 1-0 win over RB Leipzig in the first leg of their last-16 Champions League contest on Tuesday, with Brahim Diaz netting the only goal of the contest.
Los Blancos recorded a 4-0 victory over Girona in the league last weekend, meanwhile, with the result allowing them to open up a five-point lead at the summit, while they are also 10 points ahead of Barcelona in third.
The big games keep coming for Real Madrid as they will take on Sevilla and Valencia in their next two in the league before hosting RB Leipzig for the second leg of their last-16 Champions League title, and their form is even more impressive considering the injuries that the team have had to contend with this term.
Carlo Ancelotti's side are on a run of three straight wins away from home in La Liga, and they have the best record on their travels in the division this term, picking up 29 points from 12 matches.
Rayo, on the other hand, have the second-worst home record in Spain's top flight this season with just eight points from 11 matches, and Real Madrid will be confident of picking up another vital three points on Sunday.
Rayo Vallecano La Liga form:
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Rayo Vallecano form (all competitions):
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Real Madrid La Liga form:
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Real Madrid form (all competitions):
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Team News
Rayo have two injury doubts for this weekend's contest, with the home side needing to make late checks on the fitness of Pep Chavarria (hamstring) and Diego Mendez (muscle).
The capital outfit were close to gaining a point at Mallorca last time out, conceding in the 91st minute, and it could therefore be the same XI that started the 2-1 loss despite the change of manager.
However, the likes of Raul de Tomas, Oscar Trejo and Unai Lopez will be hopeful that they can play their way into the starting side under the new head coach.
As for Real Madrid, Antonio Rudiger, Jude Bellingham, David Alaba, Eder Militao and Thibaut Coutois remain unavailable for selection due to injury problems.
Brahim Diaz is also a major doubt with the issue that he picked up against Leipzig, so there could be a start in a slightly deeper position for Joselu.
Los Blancos will also have to work around the absence of Ferland Mendy, who is suspended following his milestone booking against Girona, which is likely to lead to Fran Garcia coming in.
Luka Modric is an option for change in midfield, but it seems likely that it will again be Toni Kroos, Federico Valverde and Eduardo Camavinga as the three midfielders, with Aurelien Tchouameni again needed at the back.
Rayo Vallecano possible starting lineup:
Dimitrievski; Balliu, Mumin, Lejeune, Espino; Valentin, Ciss; Palazon, K Perez, A Garcia; Camello
Real Madrid possible starting lineup:
Lunin; Carvajal, Tchouameni, Nacho, F Garcia; Valverde, Kroos, Camavinga; Joselu; Rodrygo, Vinicius
We say: Rayo Vallecano 1-3 Real Madrid
Rayo will be looking to take advantage of Real Madrid's busy schedule and injury problems, but the home side are in such disappointing form, so it is tough to back them. Los Blancos are on a bit of a roll at the moment, and we are fully expecting them to collect another three points this weekend.