Walcott has always insisted his best role is down the centre and giving the 26-year-old a chance has worked for the Gunners so far.
The England international has already scored seven goals in 13 appearances for club and country this season, and has 12 goals in his last 14 Premier League starts.
In contrast, Giroud scored three goals in 11 appearances for Arsenal so far, drawing criticism for his inconsistent displays and lack of killer instinct in front of goal.
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"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," Giroud told reporters.
"Whether it was at Tours, Montpellier or Arsenal, I have never experienced a situation like this, I have often played from the start. I need to take positives and to harden myself mentally. It is something new for me.
"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," the 29-year-old French striker added.
Giroud is not worried over his lack of playing time and is confident he will pounce on any opportunity to win back his place in the starting line-up.
"It has been for several matches now that I have played less, that is for sure, but I do not need to be worried. I need a bit more game time but also to believe more in my abilities," Giroud said.
Arsenal, who are second in the league table after eight games, travel to face promoted side Watford on Saturday.
(Reporting by Shravanth Vijayakumar in Bengaluru; editing by Amlan Chakraborty)
