The Blues take on the Eagles at the Estadio da Luz on Tuesday night in the first leg of the quarter-final showdown.
Benfica have excelled in this year's competition having helped dispose of Manchester United in the group phase.
And they now have another Premier League scalp in their sights, with the Argentine believing that the struggles of goal-shy duo Fernando Torres and Didier Drogba could play into their hands.
"I think there is an anxiety in Chelsea by the lack of goals from Torres and Drogba," said Gaitan.
"We can exploit that and even though it will be difficult to stop them, it is possible and I have confidence we will keep a clean sheet.
"Benfica are having a good season in Europe. This is our main strength against Chelsea.
"The squad is convinced we can create chances and we play without fear against anyone."
Both sides head into the encounter on the back of goalless draws in their respective domestic leagues, but Gaitan insists Benfica are focused ahead of the last eight tie.
"Both teams failed to score this weekend in the domestic leagues, but that is just luck," he added.
"It wasn't the Champions League game which caused the 0-0 scores.
"We are very focused in this knockout game because, for us, those are the matches of the year. To get into the semi-finals is to fulfil the first part of our European dream.
"The tie is very open and without a clear favourite. Chelsea are, of course, strong in Europe but we are not inferior to them."
