Girard's side walked away with the three points as Liverpool loanee Divock Origi bagged the only goal of the game in the 68th minute from the penalty spot.
"I didn't think we played very well but we were never in danger," Girard told reporters after the game.
"We were very, very average. We will not play like that against Porto in five days [in the Champions League qualifiers]. We took three points and that's what matters.
"We wanted to play a short passing game but there was a lack of speed. We didn't play well as a team and we have to recognise that."
Lille currently occupy sixth position in the Ligue 1 table after two games.