Having lost 2-1 to fellow high-flyers Peterborough Sports last weekend, the Steelmen were unable to bounce back as they produced a poor display when going down 3-1 to Thame United at Steel Park.
Kinniburgh’s team dropped down to third place as a result and the manager was unable to find anything positive to talk about in the aftermath.
He said: “We never got going, we never turned up to be honest. It was really disappointing.
“We can only apologise to the 400 people who turned up to watch us. They have been coming home and away and it was lacklustre.
“There was a yard or two missing and it was really poor.
“For a team that is supposedly going to be challenging for the top end of the league, the inconsistencies are a massive issue.
“I am going back to maybe four or five weeks ago where it started to creep in. It seems like we are slipping into that sort of form where we are half at it.
“I don’t think it was a hangover from last weekend at all, I actually thought we played alright at Peterborough.
“We just didn’t do anything right this time. We got into the right areas and we had enough balls across goal that they were clearing. We had more than enough of the ball in their penalty box but we never did anything with it.
“It wasn’t good enough defensively and it wasn’t good enough in their penalty box and they are the two critical areas in the game.”
The Steelmen trailed 3-0 before visiting defender Aaron Jewell saw red for a challenge on Jake Bettles with 20 minutes to go.
Corby pulled one back thanks to an own-goal but were unable to push on.
And Kinniburgh added: “My question is why does it take someone getting sent-off and us having to score a goal to get the boys fired up.
“Why are we not going from the kick-off and in the warm-up. That should be the ignition and that should be the time that we go and get after teams.
“We are worrying far too much about other outside influences. We need to start properly from minute one and not wait for something to ignite us into action.
“We do react well to red cards or bad challenges on a player but our transition earlier in the game is really poor.
“It looks lacklustre but then in the last 15 minutes we are running over the top of them so it’s not a fitness thing, it’s a mentality thing and we need to change it quickly.”