The Real Madrid stalwart says Fatih Terim's men deserve their place in the last eight of the Champions League, and claims the opening game will be pivotal to the tie
Fatih Terim's side are considered the tournament's outsiders but the Spain international feels the Turks pose a genuine threat to Madrid's challenge if they are allowed to register any away goals next week.
"We have to keep a clean sheet at home and score goals because I'm convinced that they're going to make it very difficult for us in Turkey," Ramos told Marca.
"Being drawn against Galatasaray isn't a stroke of luck, far from it.
"You must never underestimate a team. They all deserve to be where they are."
Three of Jose Mourinho's former players will be looking to get one over on their former boss at the Bernabeu on Wednesday, and the full-back is under no illusions of the danger their opponents possess.
Ramos added: "Galatasaray have been strengthened by the arrivals of [Didier] Drogba and [Wesley] Sneijder but danger comes from the team as a whole, which is quite strong."