Since the 1-1 draw between the teams in their first leg at the Santiago Bernabeu, Jose Mourinho's side have completed an El Clasico double over Barcelona.
A 3-1 success at the Camp Nou in the Copa del Rey in midweek was followed up with a 2-1 home league win against their great rivals.
And the players both believe that Los Blancos are perfectly prepared for the second leg tie at Old Trafford on Tuesday night.
Ramos said: "The desire is to eliminate United, but we will go to Manchester showing great respect to our opponent.
"Psychologically the team has strengthened after the clasicos but we will go into the match convinced we can go through. We know we can go through."
Meanwhile, Pepe highlighted the incredible wealth of options Mourinho has to choose from.
He said: "We have hit our best form. Apart from (Iker) Casillas we have everyone available and the manager has great solutions on the bench.
"We have achieved two important victories given the form and quality of the opponent we were playing and that gives us great motivation for the Manchester United game.
"We are happy and now we need to rest and think about the game on Tuesday."