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.
Delaplace smashed the ball home from 25 yards in the 58th minute, while Kjaer curled a free-kick into the net 16 minutes later.
"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."
Girard rested Florent Balmont, Pape Souare and Salomon Kalou against Lorient ahead of the trip to 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.
Bayer Leverkusen will also take a lead back home after coming from behind to defeat Copenhagen 3-2 in the first leg, as will Zenit St Petersburg, who won 1-0 at Standard Liege.
Napoli will have to score an away goal if they are to advance past Athletic Bilbao after the two teams drew 1-1 in Italy in the first leg, while Arsenal will host Besiktas after a scoreless draw in Turkey.
Salzburg will visit Malmo with a 2-1 advantage, while Steaua Bucharest have a 1-0 aggregate lead ahead of their trip to Ludogorets.
APOEL will host AaB, Slovan Bratislava will welcome BATE Borisov to Slovakia and Maribor will visit Celtic with all three ties locked at 1-1.
