The French striker has found the net six times already this season, but it was his creative play that caught the eye against Norwich on Saturday - with fine assists for Jack Wilshere and Mesut Ozil proving that Giroud is more than just a ‘conventional’ centre forward.
“He is vital for us, and fits in completely to what we are doing,” Mertesacker told the official matchday programme.
Read more from Per in the official matchday programme
“He’s a tall guy but technically well educated, and the important thing is that we can play on the ground with him but, if there is pressure on us, we can put the ball in the air and he can hold it in a way that I’ve never seen.
“You can use him in different positions and angles; at the moment he is the one who fits the best up front. If he doesn’t score, he’ll make assists.”
Mertesacker is looking forward to a clash of creative forces when his fellow Germans come to town - with the Champions League runners-up looking just as potent as they did last term.
“They did lose Mario Goetze, but they spent money on very good players after that,” he said. “They brought in Henrikh Mkhitaryan and Pierre-Emerick Aubameyang, as well as Sokratis, who I know very well from Werder Bremen.
“I think they’ve replaced Goetze in a good way, and you could see from the start that the new players fit into Dortmund’s game. It’s a team full of power, full of intention to create the pressure to an extent I’ve never seen before.
"We know that we’ll have to respect their game while taking good care of our own.”