The striker has found himself second choice for Arsene Wenger of late and admits he need to harden mentally.
The Frenchman has found himself relegated to the bench this season, with Walcott, who has long wanted to be used in a central striker role, being handed the starts so far.
He has impressed as well, with his performances gaining praise from a number of areas for the displays he has put in with him looking more and more comfortable in the role as he adapts from a more familiar right wing role.
And Giroud admits he must harden himself mentally for the battle with Walcott.
“I need to take positives and to harden myself mentally,” the Mirror, reports him as saying.
“At Arsenal, I am in competition with Theo for the striker position. But he is doing well at the moment, so there is no reason to change.
It is not all doom and gloom for Giroud though, as he feels that manager Arsene Wenger still believes in him.
The striker did actually start the season as the Gunners’ first choice forward, starting the defeat to West Ham, the win at Crystal Palace and the draw at home to Liverpool.
He scored in that win over the Eagles but has only started twice since, in the Champions League and Capital One Cup, and he admits it is a new situation for him.
“Whether it was at Tours, Montpellier or Arsenal, I have never experienced a situation like this, I have often played from the start,” he added.
“I was in [Walcott’s] place in previous seasons at Arsenal. I imagine what he must have been thinking. But I feel that the coach believes in me. I do not need to be worried. I need a bit more game time but also to believe more in my abilities.”