Los Blancos go into next Wednesday's match with a 2-1 deficit following Tuesday night's defeat at the Allianz Arena.
"Everyone at the Bernabeu must roar in support of the team and make our opponent feel what it's like to play at the stadium," Ramos told the club's official website.
"We'll have to try to win the tie from the start. One goal may not be enough. We'll have to go all out for a win.
"It was a shame to lose. We would have liked to leave with a draw, but these things happen in football. We faced a dangerous opponent that has great individual skill."
Madrid next face a crunch trip to Barcelona in La Liga on Saturday.