Barnet boss Darren Currie revealed Medy Elito claimed he was headbutted by Brentford's Sergi Canos as the battle of the Bees boiled over.
Brentford's 3-1 fourth-round replay win over the only non-league club left in the FA Cup was marred by an ugly 19-man brawl sparked by Elito's hefty challenge on Canos.
Canos reacted angrily and squared up to Elito, prompting the Barnet winger to crash to the ground holding his face, although any contact looked minimal at best.
Referee Roger East eventually dished out three bookings but Elito, in particular, was lucky to escape a red card.
Currie said: "He told me he got headbutted. I genuinely haven't seen it. He said he was, that's the game. He (Canos) has reacted to a strong challenge from our player."
Goals from Canos and Julian Jeanvier put Brentford ahead at half-time and Neal Maupay added a third shortly after Craig Robson hit the crossbar for Barnet.
At least the goal of the night belonged to Barnet, David Tutonda hitting a blistering consolation right in front of the raucous away end 15 minutes from time.
"In the second half thought we were excellent. it was a nice response from our chat at half time, I was frustrated in the first half," added Currie.
"In the second half we earned the respect of our opponents. If we'd got our goal at 2-0 it might have been a different story. I'm immensely proud of how we conducted ourselves in the second half.
"They are disappointed, they felt like they let the first half slip away. But they'll realise they have a lot to be proud of."
Brentford will now head to Championship rivals Swansea in the fifth round a week on Saturday.
Boss Thomas Frank said; "Job done! We're through to next round and we are pleased with that.
"When you see Newport beating Middlesbrough it proves it's not easy in this tournament.
"The first half was professional, the second half was so-so, but we did what we needed to do.
"Now we look forward to Swansea. We are one game from the quarter-finals. It's 30 years since we have been in one so we would like to do it again."
