The French striker joined Arsenal from Montpellier in summer 2012 and grabbed 105 goals in 253 appearances for the Gunners before leaving for London rivals Chelsea in January 2018.
After winning the 2017 FIFA Puskás Award and three FA Cups with the North London side, Giroud is not a player Arsenal will forget anytime soon.
Tuesday night paired the club with Ligue 1 side Lille in the Champions League, reuniting Giroud with his former club as he enjoyed being back at the Emirates Stadium.
"It was a great feeling, with special emotions. I spent five and a half years here, they haven't forgotten me. That's what's beautiful about the English," the Lille forward continued.
"I would have preferred us to get something tonight, but I am happy with this reunion with my former club," Giroud admitted.
Giroud came on for Lille and received a standing ovation from the Arsenal crowd, who were keen to welcome the veteran back to the ground.
This will be particularly special for Giroud as he spoke recently about how close he is to retirement, making his Emirates welcome likely his last before he hangs up his boots.
“As a player, I think it is very probably my last season. That's why I'm making the most of every moment.”
He also stated: “I am at peace with myself and everything I have accomplished in my career. I feel more relaxed than ever.”