Giroud notched his 50th Premier League goal with an early penalty as Arsenal went top of the table at Villa Park, four days after his first hat-trick for the club had yielded a 3-0 victory at Olympiakos that sent Wenger's side into the Champions League last 16.
The in-form France international has now found the back of the net 11 times in the last 13 matches to spearhead Arsenal's push for honours on the domestic and European fronts.
"I believe Olivier is at the top of his game," said Wenger. "He's questioned some times, but the numbers get people to realise that he's a quality player.
No Villans in this story: Arsenal go top of the league with 2-0 win over Villa
"I think he's improved technically and his link-up play is better. He may not have electric pace and he likes to play with his back to goal, so maybe he isn't a spectacular individual.
"But he's a very efficient and an important player for this team. He is also mentally very strong, too."
After Giroud struck from the spot, Welsh midfielder Aaron Ramsey netted in the 38th minute to give Arsenal a win that took them above Manchester City and Leicester City, who host Chelsea on Monday.
"It has been a great week for us," said Wenger. "But don't worry, I've had my fair share of bad weeks already, so this balances itself out.
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"I was a bit anxious today (Sunday) because we had given a lot on Wednesday night and then we came back very, very late on Thursday morning.
"I knew that Villa were fighting for survival, so it was important to take the lead against a team low in confidence.
"The second half was more difficult for us and we had to defend well. Maybe we were lucky with one or two opportunities for Villa, but overall it was a controlled performance."
It was something of a bittersweet win for Wenger as it added to the woes of his fellow Frenchman Remi Garde, the first player he signed at Arsenal.
But although the outlook appears bleak for Garde barely a month into his tenure as Villa manager, Wenger still believes he can overturn the odds and revive the club's fortunes.
"His team showed good spirit and good cohesion, but they are a bit short of confidence," said Wenger.
"I encouraged him to come to England and I think he will do a good job given the time. Of course, you don't have much time in the Premier League.
"But it is not completely a lost cause. You only have to look at what happened to Leicester last season when they were bottom for so long."
Garde still maintains that Villa can get themselves out of trouble, but knows that the next few weeks are going to be crucial as they face Newcastle United, Norwich City and Sunderland.
"We are coming to a period over the next two or three weeks when we face games which will be must-win for us in our situation," Garde admitted.
"We still believe we are capable of being safe. I know that in football you can change things with work and concentration."
He added: "Every week, we have to find some positives from our performances, which isn't easy.
"But I was happy with the way we reacted in the second half after making the worst possible start by going behind inside 10 minutes in such a game.
"I feel the referee took a long time to make his decision for the penalty (awarded for a foul on Theo Walcott by Alan Hutton), but probably it was a fair one in the end. It's right that the referee should take time."
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