LOSC lost 1-0 to Bordeaux on Sunday to end an unbeaten run of 11 games during which they did not concede a goal.
The result saw Lille slip to third in the Ligue 1 table and they could be seven points behind leaders Paris St Germain by the time they kick off on Sunday with the defending champions visiting Rennes on Saturday afternoon.
But Girard is refusing to panic affter seeing the long run come to an end and has urged his players to just carry on doing the good things that have got them into the upper echelons of the table.
"We knew that we would lose one time or another, but I have no particular worry," he told a press conference.
"It was a collective defeat. I still have a lot of confidence in my group and I know what the boys can do.
"No match is easy, we will have to react against Bastia on Sunday.
"Playing at home again is very important. We have the chance to recover in a great stadium with extraordinary football fans."
He added: "I hope that we keep the mindset that we have today no matter what the results.
"We must remain vigilant, not slack off and continue working.
"Today, we can have a respectful and humble ambition. I want the players to believe in themselves and be aware that we can really achieve something good."
Bastia are coming off a loss of their own having been beaten 3-1 by Lyon last weekend to end their four-match unbeaten run.
Coach Frederic Hantz cited playing three games in quick succession as one of the major reasons behind that defeat and he faces major injury problems ahead of the trip to the Stade Pierre-Mauroy.
Wahbi Khazri definitely remains out while Gianni Bruno, Ryad Boudebouz, Gilles Cioni, Mickael Landreau, Drissa Diakite and Julien Sable are all doubts for Sunday.
N'Dri Romaric and Yannick Cahuzac are both suspended meaning Hantz may be taking a bare-bones squad on the trip north.