The 22-year-old will be in the starting XI for Los Blancos when they line up in the Etihad Stadium next Friday - with Sergio Ramos being suspended. Real go to City needing to overturn a 2-1 deficit to reach the quarterfinals.
Militao said, "I can imagine it now, in the Champions League, in Manchester.
"The winning goal, with a header. But I wouldn't know how to celebrate it... Nothing is impossible, so I'm going to go for it.
"Madridistas, against City we will not have our captain but I am here. I'm going to have a good match, trust me. We will be victorious."