The Olympique Lyonnais coach believes his side will have to be at their best defensively to keep the Liga outfit at bay
The Ligue 1 club won the reverse fixture 2-1 on home soil in their last Group I encounter, to leave them top of the group with a maximum nine points from three games, but Garde is expecting a tough encounter as his side seeks qualification to the knockout stages.
Athletic were runners-up in the competition last season, but have struggled to replicate that form this time around and are currently bottom of the group with a single point, but Garde is predicting Marcelo Bielsa's side will try and force the issue on Thursday night.
"What worries me is that they attack the opponent constantly, and they like to have the ball and and pose a threat in attack," he told AS.com.
"Therefore we will have to defend well and also do well when attacking.
"Athletic will be competitive and strong and it will not be so easy to get the victory. Their position does not correspond to their level, a level that has already been shown elsewhere to be high."
A win for Lyon will see them secure qualification to last 32 after just four matches of the group stage, and the 46-year-old has called on his players to focus solely on the task in hand.
"My players are fully motivated and are concentrating on the match itself and not the standings, though the goal is qualification," Garde added.
"We must prepare game by game and not look ahead to other matches. That would be dangerous."