The report claims the Gunners manager tried to back out of the transfer at the eleventh hour, to pursue Atletico Madrid striker Adrian Lopez, but the deal for Giroud had already passed the completion stage.
Wenger reportedly instructed Spanish scout Francis Cagigao to watch the Atletico frontman, and Cagigao, who has recommended Cesc Fabregas, Jose Reyes and Santi Cazorla, was thought to be extremely high on the young striker.
But with the future of Robin Van Persie up in the air, Wenger was reluctant to sign both Giroud and Lopez, especially with Nicklas Bendtner, Park Chu-Young and Marouane Chamakh still taking up a significant chunk of the balance sheet.
A Goal.com source said: "He tried to pull the plug on the Giroud deal to sign Lopez instead. But by then it was too late and the Giroud transfer had already been signed off."
Once Van Persie eventually completed his £24m move to Manchester United, Wenger could have gone back for Adrian but it was too late, although the Gunners have recently been linked with a January move for the Spanish international.
The 'new David Villa' featured in Spain's Olympic team, has two caps for his national side, and is thought to be available for £14.6m - the value of the clause in his contract.
Since the departure of Robin Van Persie, Ivorian forward Gervinho has largely operated as Arsenal's central striker, although Giroud, who initially struggled to settle at the Emirates Stadium, now looks to have found his feet.