Alcacer is on a season-long loan at BVB from Barca and has scored seven goals in eight Bundesliga games.
Favre insists the reason for his success isn’t rocket science.
“As I have said before, Paco Alcácer has not played two full games in the last three years,” shrugged Favre
“When he arrived he was not ready, but he is improving day by day, of course, we have seen that he is a great player.
“But we must be careful because there are many games and he will not be able to be always play from the beginning.”