Ayoze Perez struck after halftime after Jorge de Frutos had seen red for the hosts just before the break.
Marcelino said, “The victory couldn’t have come in any other way than through suffering. There’s a reason Rayo’s record has been there this season. When you’re down to ten men, it’s much more difficult.
"We were down to ten men at La Cerámica and today they were, and that gives you an advantage. Even so, they put us under a lot of pressure and when you have a minimal advantage, you know that they can make things difficult for you in the final stretch.
"We could have sealed the win with a second goal, but we left it open until the end. But we’re satisfied with the work and the result.”
On the form of Alex Baena and Ayoze Perez, he added: “They are two very good footballers, internationals with the European champion team. They are at a very high level.
"But not just them two. I am grateful for the season of the whole squad, for the commitment they show. Having the points we have means that we are a good team.”