Neal Maupay told Arsenal to be more humble as the Brighton striker was the Gunners' villain with a 95th minute winner to secure a 2-1 victory on Saturday.
The visitors were unhappy with Maupay's part in the challenge that saw goalkeeper Bernd Leno stretchered off in the first half.
The Gunners still looked on course for the three points when Nicolas Pepe opened the scoring with a stunning strike 22 minutes from time.
But the defensive deficiencies that have haunted Arsenal's season under three different managers have not been ironed out during a three-month layoff as Lewis Dunk bundled home an equaliser before Maupay snatched Brighton's first league win of 2020 late on.
"Some of the Arsenal players need to learn humility sometimes," said Maupay. "They were talking a lot first half, the second half when they were 1-0 up, and they got what they deserved."
Maupay and Matteo Guendouzi had to be separated at full-time as tempers flared.
However, the Frenchman denied any responsibility for the injury that saw Leno twist his knee after a slight nudge from Maupay.
"At half-time I went to Mikel Arteta to apologise. I never meant to injure their keeper," added Maupay.
"I have been through a bad injury, so I know it is hard, but I never meant to hurt him."
A second defeat in four days leaves Areta's side still eight points outside the top four in ninth, having played a game more than fourth-placed Chelsea.
And Spaniard Arteta labelled the manner of the defeat "unacceptable" from a commanding position 15 minutes from time.
"It's a very difficult one to take because it is unacceptable the way we lost the game," said the Spaniard.
"We missed so many chances, the fact that we gave them the first goal and we did not compete for the second goal."
- No intention -
In keeping with all matches since the Premier League's restart on Wednesday, players took a knee prior to kick-off to protest against racial injustice.
However, slow starts have also been a feature of the first six games after a three-month stoppage and again both sides struggled to adapt to the hollow atmosphere of empty stands.
Leno has been one of Arsenal's few standout performers this season and was visibly furious with Maupay as he was carried from the field.
"I haven't seen the action again, but I always believe players never have the intention to hurt other players," added Arteta.
Arsenal posed the bigger threat for the majority of the game as Bukayo Saka struck the bar and Pierre-Emerick Aubameyang peppered Mathew Ryan's goal.
Pepe provided the moment of magic it seemed the visitors required to secure all three points when he cut onto his favoured left foot and curled just his fifth Premier League goal into the top corner.
However, they were punished for two moments of slack defending.
Firstly, Solly March was given time from a quickly-taken short corner to drive in a low cross and Dunk forced the ball over the line.
And worse was to come for Arteta as Maupay was quickest to latch onto Aaron Connolly's pass and dinked the ball over the advancing Emiliano Martinez to snatch a huge win that takes Brighton five points clear of the relegation zone.
Brighton players celebrate a vital 2-1 win over Arsenal
Arsenal goalkeeper Bernd Leno was stretchered off with a knee injury