The towering defender has voiced his admiration for the prolific attacker, while stressing that the Spanish champions could struggle to deal with Marco Reus
The Serbia international believes Ronaldo always delivers when his team needs him, and sees the Portuguese attacker as Madrid's undisputed star performer.
"Cristiano Ronaldo is a superb player. He's Madrid's go-to-guy, as the Americans say," Subotic was quoted as saying by Kicker.
"When you need something, you approach him. If there's something happening, they are looking toward Cristiano. They all know that he's always ready."
The defender then went on say that the Madrid defence will face a tough task to contain Marco Reus on Wednesday.
"Marco is a fantastic player. I honestly think there's no defender - so no-one at Madrid either - who can shut him out for an entire game. It's impossible to completely eliminate him."
Wednesday's match at the Signal Iduna Park kicks off at 20:45CET.