After being lambasted for missing a host of clear-cut chances against Burnley at the weekend, Bendtner steered the Gunners to the Champions League last eight with a 6-2 aggregate win, in which he had scored half of the goals.
"It shows you how football can change very quickly," Wenger said after the 5-0 victory at the Emirates.
"It can go quickly up and quickly down. It shows that he had not lost his confidence and he came back with a good focus and belief, that's one of his strengths, his confidence levels remain relatively stable.
"He has the size and presence that we need because we are normally a very short team...he helps us offensively and defensively."
Bendtner has been given the opportunity to lead Arsenal's frontline thanks to the long-term injury of Robin van Persie and the unimpressive form of Eduardo.
The 22-year-old is the Gunners' top scorer in the Champions League so far with four goals in three games.