Lyon have now secured just one win in their last eight matches in all competitions, and Garde admits that his team need to improve their defending.
"I am disappointed that we lost the match," Garde told reporters. "We did not deserve it, but that is football.
"I think we had done the hard part by getting the equaliser but our defending at both of their goals was naive. That said, I can't overly criticise my players.
"I think that, compared to recent weeks, we tried to play football and work well together as a team. But we were defensively fragile."
Lyon host Lille at the Stade de Gerland on Saturday.