Robbie Neilson said he was disappointed with the four official Chris O'Donnell after the Dons boss was sent to the stands with five minutes to go in the 1-1 draw with Oxford on Saturday.
With the thrilling encounter finely poised with five minutes to go, Neilson was furious when he saw Gboly Ariyibi taken out off the ball in front of his dugout - an incident that went unnoticed by referee Dean Whitestone.
Dons went on to win a corner, but the referee was called back by the fourth official, and Neilson was sent to the stands.
Neilson later explained: "He said I kicked the water bottles at him - it would have had to be one hell of a kick to reach the fourth official 40 yards away. I was just disappointed in the way it was handled.
"I've been there before, sometimes you just put your hands up and go into the stands, but today, for me, was an over-reaction from the fourth official who found it difficult to handle two quiet dugouts.
"I thought there was a terrible take out - a body slam in front of us, and I reacted. The fourth official reacted to it too, and I was put into the stand.
"I've spoken to the ref and expressed my disappointment because there is a process - you should be spoken to, given and warning and then you're put into the stand after that. But I didn't think it merited anything like that.
"If he came over and chatted to me with five minutes to go in a huge game for us, after a horrific take down, you have to react. If you don't react to that, then you shouldn't be in the game. I was disappointed with the fourth official. His handling was very poor."
On the pitch, Dons handed starts to Alex Gilbey and Scott Golbourne after signing on deadline day, trailed courtesy of a Rob Hall strike after just eight minutes before substitute Callum Brittain netted an equaliser - his first goal for the club - on the hour.
Neilson was impressed with his goal-scorer, and indeed all of his signings, with Aidan Nesbitt coming off the bench late on.
"They were all exceptional," he said. "Golbourne showed his quality. Gilbey drove the midfield and gave us a totally different option and Nesbitt showed his quality. He still has a long way to go - he has to bulk up and understand the game here but high up the pitch, he has that moment that we need.
"Callum's a huge prospect for us. From the day I arrived, I said he was the one who has the potential to do really, really well here.
"He has a really good attitude and he wants to do well. He has natural ability and athleticism so he slotted right in. We had options - we could have brought on Cisse, or Lewie and shoved everyone across. But I felt bringing George into the centre gave us some pace and Callum gave us an attacking threat.
"I thought we found the first 20 minutes difficult but after that we control a lot of the game. We were the better team and managed to get back into it. I thought we could have gone on to win it until the last five minutes when it became like a basketball game.
"I hope it's a springboard, but I'll tell you next Saturday. That's the standard we've set now. We've played a really good team and dominated, and looked positive. We should have Agard and Sow back next week to add some fire power and hopefully we can push on now."