Lehmann started the season between the posts for The Gunners but made a couple of costly goalkeeping blunders.
Almunia has come in and looked assured, with Arsene Wenger claiming that Lehmann was not available due to an Achilles problem.
"I am without a doubt mentally the strongest player at Arsenal because I have more experience," Lehmann claimed in The People .
"There will always be a keeper who will play better for two or three matches but I have never seen anyone do this for ten games.
"I know that I have an advantage at Arsenal and that I can keep it. I don't see any young supermen keeping me out."
Wenger has told Lehmann that he cannot expect to just walk back into the side, but the 37-year-old is confident it will only be a matter of time before he reclaims his place.
He said: "I know I will be playing again at Arsenal. The coach will let me play.
"He knows it, and I know it - it doesn't matter if I have another week out.
"I have read that Almunia said he deserves to be the No 1 but until now he has not won a single important game."