The Ivory Coast international struck twice in the Coppa Italia semi-final first leg on Wednesday, including the 88th-minute winner.
Gervinho made a good start in Italy after his move from Arsenal and his recent form has been even better, scoring four times in the past three matches in all competitions.
Garcia said it was just what he expected and believes having faith in the 26-year-old is the key.
"Am I surprised Gervinho is doing so well? Absolutely not. I think he can do a lot better, as he has some things to work on," Garcia told Rai Sport after the win over Napoli.
"Above all he needs the faith of his coach and his team-mates, as he said this week that when he gets the ball he plays either to provide an assist or to score.
"Things are going very well for him and for Roma."
Gervinho was lucky to open the scoring as he latched onto Francesco Totti's pass from an offside position before finishing.
His sealer – after Napoli had come from 2-0 down at half-time – was on the back of a neat team move and another good finish.
Garcia lamented the way his team started the second half and said it was '50-50' as to who would reach the final.
"The start of the second half caught us napping," the Frenchman said.
"I said at the start of my half-time talk and again at the end, as I knew it was fundamental, that we had to start strong.
"We had a two-goal advantage, but started the second half without aggression. I always say attack is the best form of defence.
"I think the chances of qualifying are 50-50. We know that we can score against Napoli, but also that they have a very strong attack. If we see another game like this, it's a good advert for football.
"Roma can certainly improve, as tonight we conceded two goals, which we've hardly done all season.
"Above all, we mustn't lose this desire to win, as that is the great strength behind Roma. Every player is utterly determined to get the victory and we cannot lose that."
