Carlo Ancelotti's side were held to a 2-2 draw with Valencia on Sunday and remain in third place as a result of that setback.
The UEFA Champions League finalists needed a stunning stoppage-time effort from Cristiano Ronaldo to even salvage a point at the Bernabeu.
Atleti's 2-0 defeat at Levante on Sunday gave their neighbours and Barcelona some slight hope in an enthralling battle for the title.
With Atleti - who face Ancelotti's men in the Champions League final on May 24 - and the Catalan giants meeting on the last day of the season, the title is still in their hands.
He said: "It's still difficult. It's as I've always said - this league is going to be decided in the last few games.
"There are three games to go that we have to win. It won't be easy, as we play two of them away against teams that have something to fight for.
"We must be clever and prepared. The drive to win is the same as always."
Ronaldo's cheeky backheel was his 50th goal of the season, a sensational landmark that he has achieved for four seasons in a row.
And Valladolid – unbeaten in their last 11 home matches - will have to keep a close eye on the Portugal captain in a game which gives them the opportunity to move out of the relegation zone.
Juan Ignacio Martinez's side breathed new life into the battle to avoid relegation with a precious 1-0 win against Espanyol on Saturday.
That was their first win in five games and just a point against Ancelotti's charges would be enough for them to move above Osasuna, Getafe and Almeria into 16th spot with games against already-relegated Real Betis and fellow strugglers Granada to come.
