Leyton Orient manager Ross Embleton accuses Mark Cooper of making ‘unacceptable’ comment about Justin Edinburgh
Interim boss Embleton was sent to the stands in the first half of his side's 4-2 defeat to Rovers after throwing his chewing gum at Cooper.
He claims he was called an "impostor" and then asked "who do you think you are, Justin Edinburgh?" during a row.
Forest Green released a statement firmly denying the accusation.
Edinburgh, who had led Orient since November 2017 and guided them to the National League title last season, died in June at the age of 49 after suffering a cardiac arrest.
"I got told I was an imposter in terms of being in and around the environment I am in," Embleton told the club website.
"But it's great because I have spent most of my life being an imposter. I didn't play football or have a football career and I've worked extremely hard to get myself to where I am and where I've been in my coaching career.
"It's a thing that's been thrown at me quite regularly, which doesn't affect me anymore as I quite like it, it's my thing. A lot of people don't know my name and don't know who I am. So, I can accept that bit.
"But to follow that up with 'who do you think you are, Justin Edinburgh?' is something I will never accept.
"I have to apologise to everyone associated with the club - the fans, the players - for getting sent off because it obviously has an effect on the team and it shows a lack of discipline which I would never want my players to show."
He added: "However, at the same time, if there is anyone out there who ever wants to try and get me sent off again, use that phrase. That is totally unacceptable. I knew of Mark Cooper's behaviour at times and the way in which he approaches different people and today's shown me what he's all about.
Embleton was originally placed in interim charge of Orient following Edinburgh's death.
He was re-appointed to the post when the club sacked Carl Fletcher earlier this month after just 29 days in charge admitted he did throw chewing gum at Cooper.
"I got sent off for throwing my chewing gum at him and ultimately that is what I deserve.
"However, it was either that or do something a lot more aggressive which would have been even more naive of me and I would probably spend a lot more time in the stands than perhaps I'm going to.
"It was the best way for me to deal with it right at that moment in time. My blood is still boiling."
Forest Green chairman Dale Vince tweeted a statement which said: "Mark denies saying this or anything like it, he and Justin were close friends.
"The referee and the fourth official have both confirmed this evening that they heard nothing said and the fact is that Leyton's manager was sent off for throwing something at our bench after the first goal was scored.
"Their manager has to look at himself for the reason for his behaviour."
Forest Green added in a later statement: "The club firmly denies these accusations and will co-operate fully with Leyton Orient in any investigation that may come in the wake of the game.
"Justin was a close friend of the manager and deserves the utmost respect."
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