Middlesbrough boss Kim Hellberg accused Southampton of cheating after Saints manager Tonda Eckert walked out of a tetchy post-match press conference when refusing to answer questions related to 'spygate'.
Southampton were charged with a breach of EFL regulations after a member of staff was alleged to have spied on Middlesbrough's training ahead of their Championship play-off tie on Saturday, which ended 0-0.
Eckert faced multiple questions on the situation but refused to answer beyond the club statement on Friday night.
Eckert also denied that it had been a frosty handshake with Hellberg pre-match, before adding: "I have said more than enough. The questions keep coming up but the club have made a statement yesterday evening and that is all there is to say."
The club press officer stepped in and said Eckert would not be answering any more questions unless they were about Tuesday's second leg. When the next question about 'spygate' landed, with the reporters in attendance insisting that Eckert hadn't answered their questions, they walked out together.
Speaking after the stalemate, Boro boss Hellberg pulled no punches in his assessment of the incident.
"I couldn't believe my eyes or ears. Couldn't believe it when I was told a second time, or third," the Swede said.
"It's quite clear that they - and I don't mean the players or fans of Southampton, I think they are brilliant and have nothing to do with it - but someone has made a decision to cheat.
"We were trying to focus on the session as much as we could, we had an important game. I’ve seen some saying it's not a big advantage but it is. Take today for example. We have never used that first-half shape before, that was impossible to know. It’s just unfair, and I think everyone in this room agrees.
"I feel anger, but there has to be respect too between each other that they have totally failed in. I think it’s disappointing because it’s a big game. They tried to get an advantage in an unfair way.
"Who would get the fine? Should they pay it to the EFL? Okay. So they see everything we do, and…we will see what happens, I don't know. I just think it's weird they try to cheat in this type of game. Didn't [Marcelo] Bielsa pay £200,000 when it wasn't a law? I think a lot of clubs would pay that amount to try and get the advantage two days before a game.
"You don't do this, you don't plan to do this. Every team in the Championship should be angry. It is wrong, it is wrong!"
When asked if there is now a suspicion Southampton have done this to other clubs this season, Hellberg added: "I'm just thinking about now…and we found them in the bushes."
Southampton declined to comment in response to Hellberg's comments.
