The French outfit lead 1-0 from the first leg at the Stade de Gerland thanks to Milan Bisevac's 64th-minute header.
Ahead of the second leg at the Letzigrund stadium, Garde conceded that all eyes are on his side as they are expected to progress to the final preliminary stage.
"There is always pressure," Garde told reporters. "We want to play in the Champions League. That is our own pressure. We have a chance to qualify and that's all we are focusing on.
"We are not solely focused on scoring or keeping a clean sheet. A match of football is about balance. My squad is quite young and inexperienced and not necessarily capable of managing and controlling a match in that manner. Our strengths are in playing good football.
"We are more likely to score goals than spend 90 minutes defending. But we also have to be clever. It's the halfway point of this tie and we're leading 1-0 and an away goal will count double."
The match kicks off at 8pm on Tuesday.