Rayo have won their last three in the league, with that run of form moving them out of the relegation zone into 16th, while Valladolid currently sit 18th, three points behind.
"If we can keep taking things forward, we'll be on the right track," Arbilla told reporters.
"We're in spectacular form at the moment. We're not making the sort of mistakes we did before, which is something we had to cut out of our game.
"We'll be going to the death against Valladolid. There's more pressure on them."
Rayo have lost 17 times in the league this season – the same number as basement side Real Betis.