A Manchester City staffer had to pull Haaland away as he appeared to become incensed by a member of Arsenal's team.
Haaland then made a gesture towards the offending party, telling them to calm down with his hands.
Walker was also involved in the melee and a new camera angle on the incident showed it started after words were exchanged between the defender and Arsenal set piece coach Nicolas Jover.
It's not clear what Jover, who worked at City between 2019-21, said to Walker, however it's clear the City duo were not happy with it.
Guardiola said in his press conference about the incident: "I know what happened but I don't want to say anything."
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The moment occurred directly after the full-time whistle as City players descended down the tunnel.
Guardiola's men took a dramatic loss in a crucial clash for Arsenal at the Emirates on Sunday afternoon.
Gabriel Martinelli's deflected shot late into the contest settled the match while Haaland was anonymous throughout.
The Norwegian cut a frustrated figure and often a lonely one up top, largely isolated out of the match.
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William Saliba and Gabriel Magalhaes effectively marked the striker out of the match, who finished the game with a 0.00 xG.
And Haaland appeared to vent his fury at full-time as the Arsenal players paraded around the Emirates pitch applauding the vociferous fans.
While it is unclear who irked the 23-year-old, he was forced away from a potential melee as frustrations got the better of him.
Arsenal's 1-0 win was by no means a Premier League classic - and neither side would have complained had it ended 0-0.
Both teams are missing key players, including Bukayo Saka, Kevin de Bruyne and Rodri.
However, Mikel Arteta will not mind one jot after finally ending Arsenal's hoodoo against City, who they had lost to 12 times in a row.
With a Premier League title race in the offing, it was vital that the Gunners landed three points.
And by doing so, they have leapfrogged them in the table, jumping into second.
Just they and north London rivals Tottenham, who are top of the Premier League, are the only two sides unbeaten in the league this season.