Sheffield United forward Billy Sharp accused Wrexham's players of being "disrespectful" to the EFL Championship team after scoring the goal that ended the FA Cup hopes of the National League side owned by Hollywood actors Ryan Reynolds and Rob McElhenney.
And the bad feeling between the two sides spilled over after the game, with an ESPN source witnessing a confrontation between the two sets of players in the tunnel to the dressing-rooms and verbal insults exchanged.
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Sharp's goal in stoppage time of a fourth-round replay at Bramall Lane put United 2-1 ahead before Sander Berge scored a third goal for the home side moments later.
United, who sit second in the Championship and are on course for promotion to the Premier League, had been held to a 3-3 draw in the original tie at Wrexham nine days ago.
But with the winners of this replay set to face Tottenham at home in the fifth round, Sharp said that Wrexham failed to show respect to his team prior to being knocked out.
"I am glad we've beaten them," Sharp said. "They are doing well in their league and we are doing well in ours but I wasn't happy with a few of their players there. They've been disrespectful.
"The way they've been as a club before the game, eyeing up Spurs before the game. They had not even beaten us.
"They thought we would just roll over when they got back in it, and I think the referee was helping them as well. I don't think he gave me one foul all night."
Wrexham captain Ben Tozer fired back at Sharp after the match.
"He should show more respect to us, and telling us to "Shove it!" on the documentary, I feel like it's just fabricated stuff in his head to make it acceptable for himself if I'm honest with you," Tozer said.
"I said to him as well, face to face, he should show a bit more humility. We've congratulated them on the win, we haven't come in sulking, we've walked down the tunnel as normal. It's just a shame really that that's the way it ended.
"Apparently they were tweeting tickets for the Tottenham game before this game was played, and you had people like Oli McBurnie I believe in the press saying stuff.
"I don't believe any of our lads have said anything disrespectful, we certainly approached the game properly, but if that's the way they want to be then that's the way they want to be."
Wrexham manager Phil Parkinson said: "I was a bit disappointed with Billy to be honest -- shouting down the tunnel.
"He is a fantastic player. Well done, Bill. But I think he was disrespectful. The message to Billy is: 'You're better than that. Our players are humble people.'"
United will face Spurs at Bramall Lane on March 1 after overcoming Parkinson's team.