Referee Martin Atkinson awarded the Gunners a spot-kick after Chamakh went down in the area under pressure from Scott Dann and Samir Nasri duly took the opportunity to score.
It was a crucial decision with Birmingham leading 1-0 at the time and, after Nasri's equaliser, Chamakh scored from open play to secure a 2-1 Arsenal victory.
Dann later hit out at Chamakh, saying he had 'conned the referee' and was 'already on his way down' before there was any contact.
The Moroccan striker has responded by pleading his innocence, insisting that he would never have gone to ground if he had not been touched.
"There was definitely a contact - the Birmingham defender touched me and then it was all about the ref, to give it or not," he said in the Daily Mirror.
"For me there was contact, he definitely touched me and then the referee judged.
"If they think it is not a penalty then they can be disappointed but for me I was definitely touched and I fell because I was touched otherwise I wouldn't have fallen down in the area.
"If they believe it was not a foul and they were one-nil up and obviously it changes the game a bit then it's normal that they will feel disappointed now. But for me it was definitely a penalty."
Chamakh has adjusted quickly to the Premier League and feels Arsenal can go on to win the title despite already finding themselves five points behind leaders Chelsea.
However, he does not believe the Gunners can afford many more slip-ups if they are to emerge triumphant.
He added: "I still believe we can do it - when you see the way we are playing and the team we have, it's not a problem but it will not all depend on us.
"I believe we'll have to win all the games and then see what Chelsea and Man Utd, the others, the teams above us, do. Almost every game has to be won, there's no place for any other mistake now.
"I set myself some time to adapt to English football and it seems this time is going quicker than I thought so five in nine or ten games is definitely more that what I thought at this time of the season."