Porto won 1-0 at Lille in the first leg last week, claiming a significant advantage over the French club as they look to claim one of 10 spots remaining in the Champions League group stage.
Lille struggled at home against Porto, with the visitors controlling 59 per cent possession and taking six corners, compared to just one for Girard's side.
But after watching Lille's second-half performance versus Lorient, with goals from Jonathan Delaplace and Simon Kjaer, Girard argued the Ligue 1 club are better placed to challenge Porto at the Estadio do Dragao on Tuesday.
"We produced a great second period with the game and two goals. And I think we needed a half with that level of effectiveness to come back," the 60-year-old told Lille's website.
"Once we found the flaw, the story of the game was different, the spaces opened. When things are not smiling at us, we had the merit of believing all the way and do everything necessary to achieve our goals.
"It's comforting for the future and the best preparation for Porto."
Lille are looking to qualify for the Champions League group stage for the third time in the past four seasons, after missing out in 2013-14, although they must overcome a club in Porto who have played in Europe's premier continental club competition in 10 of the past 11 seasons.
