Second-placed Roma had gone 17 games without loss in the Italian top flight this season, but were defeated 3-0 by leaders and champions Juve on Sunday.
Goals from Arturo Vidal, Leonardo Bonucci and Mirko Vucinic condemned Garcia to his first loss as coach of the capital club, while the Frenchman also saw Daniele De Rossi and Leandro Castan sent off at the Juventus Stadium.
However, Garcia believes Roma have the necessary character to bounce back and mount a title challenge.
"I am 100 per cent confident in my players," he told Sky Sport Italia. "After a defeat we have to push forward and use the feelings of disappointment we have tonight in our future games.
"It wasn't an issue of tactics, strengths or weaknesses. Every game is different.
"Now we must keep a low profile and work even harder to win this type of match.
"Don't forget there will be a Roma-Juventus encounter in May and nothing has finished today."
Roma face a Coppa Italia clash with Sampdoria on Thursday before returning to league action against Genoa next weekend.
