Valladolid boss Juan Ignacio Martinez claims his side will need "1,000 eyes" to keep an eye on Real Madrid's attack when the sides meet on Saturday.
Los Blancos have scored a remarkable 25 goals in their last six games since their 2-1 defeat to Barcelona on October 26, including four in their midweek thrashing of Galatasaray despite being down to 10 men for the majority of the match.
"Madrid leave you with very few options. It's clear they are superior and we know it will be difficult, but in football nothing is impossible, although we will have to go out there with a thousand eyes because in the game last Wednesday they scored four goals with one less player," Martinez was quoted as saying by Marca.
"Their transitions are very quick and they have three players up front with tremendous quality and pace. They play between the lines, on the counter, shooting from distance - they have it all.
"We are excited and eager to do well on a big stage. For these games, you don't need to fire the players up because they go there already motivated."
Valladolid head into Saturday's clash with just 12 points from their opening 14 games, while Madrid sit third in La Liga on 34, six behind leaders Barcelona.