Holt was asked to step in for Saturday's home date with Fulham, and grabbed his first goal for the club in a 2-1 defeat.
He said in the Birmingham Mail: "When someone does what Christian does they are always big boots to fill, but you can only do what you do.
"I'll just play the game the way I do and everyone else can make their own mind up.
"People will say I played well on Saturday and there will be people who say I didn't. Some people you can't keep happy, it's just football.
"I've been waiting to play and you don't want minutes because of what's happened, but when it comes it's an opportunity to rise up and put a performance in."