"One win doesn't make anything happen and we have to back it up. I hope it will be a psychological boost but only time will tell.
"The top three all had the same record over the last six games so this was an important win.
"We knew we'd have to play well to get a result and we did."
Noel Hunt opened the scoring while suffering the affects of a head injury for the second time this season.
He has no memory of a goal he scored against Burnley in October after being knocked out in the process but appeared fine when bending in a 25-yard free-kick only to come off minutes later.
Coppell said: "He got a hell of a whack on the head. He did it once before this season and scored in that game as well so I couldn't tell you how it was affecting him.
"When you get one like that you see stars and lights and all sorts and it was like a scene out of Emergency Ward 10 on the sidelines at one point.
"But we've got Shane Long on the bench who thinks he should be playing every week anyway so I wasn't going to prolong the debate about whether he stayed on or not."
Blues boss Alex McLeish was disappointed to see his side lose 2nd place but it's not over yet.
"We had chances but Reading were more clinical than us and it's obviously disappointing.
"But it doesn't decide anything. They are above us in the table on December 20 but the league will go right to the wire.
"If you concede the goals we did you can lose to anyone.
"They are an efficient side who do the simple things well. They are not a beautiful passing side but they all know what they are doing and they're hard to beat."
McLeish refused to be drawn on speculation surrounding targets in next month's transfer window but admitted he is not short of options.
He said: "We'll always look at other players who can improve the team but we won't bring in anyone who isn't better than our first XI.
"If everybody is fit then we are fine but we've had four or five out recently and all of a sudden we look like a small squad.
"I am being inundated with calls from agents. It's silly season and there is no shortage of players on my desk."