Giroud, whose goals fired Montpellier to the French title last season and into the Champions League, struggled initially after his 13 million pounds move to North London.
After failing to score in his first seven games for Arsene Wenger's side, unflattering comparisons were being made between him and Dutch goal machine Robin van Persie, the man he was signed to replace.
There are signs that Wenger's faith in the 1.93m target man was well founded as the goals have started to flow.
"He has been back on target. He went there to enjoy, to make things work, to score goals, and he knows how to score," Girard, whose side have struggled without Giroud, told Reuters.
Giroud has scored four goals in the last three games and five in the last five, endearing himself to Arsenal's fans with one in his first North London derby against bitter rivals Tottenham Hotspur on Saturday.
Girard has enjoyed seeing his former charge begin to replicate the form that helped him score 25 goals in 43 appearances for Montpellier last season, although he hopes to keep him quiet on Wednesday.
"We will try everything we can to prevent him from scoring against us," he said.
"He is skilled, he is a hard-working guy, he wants to succeed and I have no doubts he will."
