Damien Duff let loose on his Shelbourne players with a half-time tirade during their 1-1 draw against Cork City.
A fan video from outside the Turner's Cross changing rooms caught some of Duff’s "ranting and raving" through an open window after a below-par first half.
Post-match, the Shels supremo suggested his side "probably had one eye on Dublin Airport and not on the game" ahead of the mid-season break.
Duff said of his half-time rant: "I haven't done that in a long time, and I wasn't planning it, but sometimes you are driven towards it.
"You can talk tactics and subs, but sometimes when a manager vents, it's for themselves. That wasn't for myself. It was to get a reaction out of them.
"Does it usually work? No. Did it work in the second half? We were better. Was it because of that? I don't know.
"It could have been the subs. It could have been our application.
"The first half wasn't a Shelbourne performance. It wasn't a performance befitting champions.
"To win a league again and be up there or thereabouts again, you need a bigger edge. Everything has to be better than the year before, and it hasn't been. That's why we are where we are."
Duff also admitted that he "fought tooth and nail" with some of his players over their holidays.
When asked about the mid-season break, he replied: "I have never liked it. The flipside is it has come at a good time for us as it's a time for reflection, but I don't like it.
"There's an air of the jolly boys outing. They are meeting at the pub in the terminal. It's a week on the gargle. That's not the football education I had in England.
"People probably think I am unfair saying it. I think it's ingrained in the culture here. It's ingrained in my guys. I fought tooth and nail with my guys. I am not happy with some of my guys on it, but that's for another day.
"But they have had a different football education to what I've had. I was taught differently, and that's why it doesn't sit right with me."
At the league’s halfway mark, fifth-placed Shels remain nine points behind front-runners Shamrock Rovers. But Duff insists his side are not out of contention.
"There's a long way to go. We are still alive and kicking. We still have a heartbeat, and I know it because they are great guys.
"We have certainly dropped a lot of points along the way with basic individual errors when we have dominated games. Different story here.
"I love challenges. It gets me excited. If it doesn't excite our players and the club, the second half of the season, be it the FAI Cup, Europe, or chasing Rovers down, then they are in the wrong place.
"Nine points is a pretty big gap, but if you have a decent fortnight in the League of Ireland, you can claw it back.
"I wouldn't say it's a big challenge. I have always embraced big challenges. Taking over Shelbourne Football Club was a hell of a big challenge.
"There's an air of the jolly boys outing. They are meeting at the pub in the terminal. It's a week on the gargle. That's not the football education I had in England"
"Cup final the first year, Europe the second year, won the league the third year. They are big challenges, but we overcome them, because that's what we do."
For the second time in the past month, Duff made a triple substitution at half-time, including the return of Paddy Barrett in defence.
"It could have been more. Absolutely could have been more," said Duff.
"We can't waste 45 minutes. We talk about not wasting a moment, an action, you can't waste a half of football.
"It's a common theme here: if you waste a half, you are coming off.
"They are not decisions which should make you nervous or afraid of giving the ball away. When lads come off lacking energy and spark, and there's a flatness about them, that's why.
"Unbelievable quality all week, and then maybe they thought they could roll into Turner's Cross and turn Cork over. It doesn't happen like that in Turner's Cross.
"Maybe they have stopped listening, I don't know. Sure, we got a reaction in the second half, and even in the first half, you can say we showed resilience getting in at 0-0 because the fire was coming."
