Casillas expectant for Real
By Francisco Acedo
Last Updated: 01/01/70 1:00am
Real travel to Stade Louis II on Tuesday evening with a 4-2 advantage from the first leg and are favourites to progress.
With Monaco heading into the tie on the back of a disappointing 3-3 draw at home to Ajaccio, Casillas is optimistic of a place in the last four.
"It is necessary to go there and, if we have to suffer, we will suffer," said Casillas.
"We want to be in the semi-finals.
"It is necessary to change our tactics a little and to think that we are gambling on having a place in the semi-finals of the European Cup.
"They come into the match having conceded three in their last league game and that makes us go there with greater confidence."
Fernando Morientes, who is on loan at Monaco from Real, netted the French side's second goal at El Santiago Bernabeu to keep his temporary club in the tie.
Spain international goalkeeper Casillas is aware of the threat posed by Morientes but feels Real have the capacity to score in Monaco.
He added: "We are certain that we will score so as not to complicate the possibility of going through.
"We know that they will not throw in the towel and if they score early, they will make life complicated for us.
"If Morientes scores three and we score three, there is no problem."