The Kiwi outfit claimed a 34-4 victory at Accor Stadium but the big talking point will be Mitchell's availability over the coming weeks as Souths fell to a 1-4 start.
Already without Campbell Graham, Alex Johnston and Jai Arrow to injury - and after losing halfback Lachlan Ilias to a broken leg earlier on Saturday in NSW Cup action - Mitchell is almost certain to spend time on the sidelines.
Mitchell appeared to lead with his elbow, making contact with the head of Warriors halfback Shaun Johnson as the Rabbitohs No.1 brought the ball off his own line in the 18th minute.
Penrith great Greg Alexander said in commentary for Fox Sports that the act was "blatant", later adding: "I don't know what goes through Latrell's mind at times in a game."
Latrell Mitchell is stopped in his tracks by two Warriors defenders. (James Gourley/AAP PHOTOS)
Mitchell was cautioned for a dangerous throw in the 31st minute on Tohu Harris after lifting the Warriors captain through the horizontal.
"They're both stupid things. You've got to be better, simple as that," Demetriou said.
But the South Sydney coach refused to condemn the fullback, whose track record is starting to count against him.
"I'll have those conversations (with him) during the week," Demetriou said.
"It's not something for me to talk about right now.
"As a group, we'll be honest as we are every week and have a look at things we need to be better at."
It leaves Mitchell facing suspension ahead of a testing run for the Bunnies, who face Cronulla, Melbourne and Penrith over the next month.
His ill discipline proved to be Souths' undoing after a positive start where Izaac Thompson slid through the Warriors' defence and touched down after five minutes.
It was the best South Sydney would play all afternoon with Rocco Berry breezing through some limp Rabbitohs defence to put Andrew Webster's side ahead after Shaun Johnson converted.
In the 13 minutes between Mitchell's two indiscretions, Souths made four errors and were offside three separate times.
After he was placed on report a second time the Warriors eventually made the Bunnies pay, Jackson Ford and Johnson crossing in quick succession to give the New Zealand side an 18-4 halftime lead.
NICOLL-KLOKSTAD � MAGIC JOHNSON 🪄— NRL (@NRL) #NRLRabbitohsWarriors pic.twitter.com/s6HzyfdL6pApril 6, 2024
Johnson darted over soon into the second half before returning fullback Charnze Nicoll-Klokstad sent Roger Tuivasa-Sheck over in the corner in his 200th NRL game.
Warriors five-eighth Te Maire Martin cruised past some pathetic defence in the 70th minute, prompting a large section of the 13,184-strong crowd to make for the exit.
The win is the Warriors' first over the Rabbitohs since 2018 and is only likely to ramp up the pressure on coach Demetriou.
"We need to pick it up," he said.
"Our main focus is reviewing this and moving on to next week, your season can change quickly with a few wins in a row but we need to be honest."
