The managers of Celtic and Dundee United both complained of "reckless" challenges as the visitors left Tannadice with a 1-0 victory.
Neil Lennon took aim at United's Gavin Gunning, while Jackie McNamara was critical of Celtic captain Scott Brown.
Celtic defender Mikael Lustig was carried off after falling awkwardly in a joust with Gunning.
But McNamara defended his player, saying: "I think he went for the ball and they came together."
Lustig appeared to be in real distress when a stretcher was called for early in the second half.
"I thought the challenge on Mikael was reckless to say the least," said Lennon.
"There is no fracture thankfully, it might be ligament damage. It is a relief because he is a top player."
Gunning, who was returning from a two-game suspension, denied the accusation, saying: "I didn't think there was much in it.
"We both just went for the ball and I landed on top of him but there was no malice in it. I went in after the game and he was okay, so it couldn't have been that bad."
McNamara then highlighted what he thought was a dangerous tackle from Brown.
"I think a reckless challenge would be Scott Brown on Stuart Armstrong, I would say that was reckless," said the Tannadice boss.
Armstrong conceded the foul on Anthony Stokes that led to the Celtic striker curling in a wonderful free-kick to win the game on 87 minutes.
And United complained that Stokes had moved the ball to give him an advantage.
"Once the referee has set the wall, he's moved the ball back a few yards," said McNamara. "That's what I was irate about."
Lennon was delighted with Stokes' contribution in a "huge performance and huge win", admitted the Irishman was closer to earning a new deal.
"I don't think he can do much more," he said. "He is a very important player to us now."