Madrid have been heavily reliant on Cristiano Ronaldo since the turn of the year, with the Portuguese forward scoring 21 of his side's 44 goals in 2013.
He told FIFA.com: "Last season with four chances we would score three goals, we were scoring goals with great ease and the only one who has maintained a similar average has been Cristiano.
"All the others have gone down in their numbers of goals and obviously the team feels the consequences.
"The goals will come. If they don't arrive on Wednesday, then we hope they will do so in the next game, but it is a reality that we are having some difficulties in scoring goals."
The Spanish giants host Galatasaray in the first leg of their quarter-final tie tomorrow night.