Girard's men won for the first time in 14 matches in all competitions, which saw them rise into 12th in the Ligue 1 table with a game in hand, but Toulouse coach Alain Casanova declared his side had very little chance of victory after Maxime Spano was sent off in the first minute.
For Girard, the most important thing was claiming three points, although he admitted Lille had stuttered late in the first half, following Djibril Sidibe's opening goal.
"This is an important victory because it leaves us with a league position which can put us at a bit of ease," Girard said.
"We were not in the quicksand but it was good to win and take the three points.
"It was very good first 20 minutes but paradoxically, when we scored, our old demons crept back into our heads.
"But after we managed to make a difference, which is not always easy, even against a team that is weakened. We'll have to string more wins together to get us back to the top of the table."
The game turned after just 30 seconds when Spano hauled down Divock Origi from behind as Lille's striker burst into the box and the Toulouse full-back was promptly shown a red card.
Although Marko Basa's spot-kick was saved by Toulouse goalkeeper Ali Ahamada, Casanova conceded his team never recovered.
In the seventh minute Sidibe made it 1-0, while a stunning half-volley from Ryan Mendes doubled Lille's lead five minutes after the break, before Nolan Roux wrapped up the home side's win 13 minutes from time.
"The early red card made it difficult. It was not the best start to an important game," Casanova said.
"Even if the penalty was saved by Ahamada, we knew that the evening was going to be difficult.
"We should have defended better because we conceded a goal too soon after that. After the second goal early in the second half, the match was over."
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