When asked at the post-match press conference on Thursday night for a reaction to the jeering from his own supporters, O'Brien did not hold back.
"It's really disappointing," he responded.
"I know the scoreline is not what they want, but to boo the effort that went into that first half from a really young team, the people that booed don't know anything about rugby league ... and they are probably the ones that cheered at the end too.
"It disappoints me that they'd do that. I thought the first half, we defended our hearts out and you've got to remember it's a really young footy team there.
"I know people are disappointed with us - but they are trying their backsides off."
Some supporters and pundits jumped on O'Brien's comments about the disappointed supporters being unknowledgable, including Fox League presenter and former Newcastle player Matthew Johns, who described them as "a bit rough".
Johns went on to explain: "Those Newcastle people from days when I played right through ... we used to get boo’d off sometimes and you cop it, because those fans turn up even when it’s pissing rain, hail or we’re sitting bottom of the ladder.
“They always turn up and they pay their money and they’ve supported that side for so long, I think they’re entitled to air their grievances.”
Johns' fellow broadcaster Andrew Voss went even harder on SEN the following morning, slamming O'Brien as "cocky".
"You pay your hard-earned money to watch your team, and if your team stinks up the joint on a regular basis, are you entitled to boo? O'Brien obviously walked into the presser feeling cocky because his team came back to win."
After some overnight consideration and/or some counsel, O'Brien explained he was simply attempting to defend the pride and commitment of his players.
"I apologise unreservedly to our members and fans that I offended, and I can understand why they would be offended," he said to the media reading a written statement.
"I was not prepared for that question, I was unaware that there had been some booing.
"I went straight into protection mode for our playing group. That's not an excuse.
"That's not how I feel about our members, I understand that we're here because of those people.
"They are an educated fanbase, they are an educated crowd. They sit through all types of weather and all sorts of scorelines with unwavering loyalty, and I'm disappointed that I let them down with an emotional response.
"I hope by owning this I can earn back a bit of their respect, because that's not how I feel about them."
The Knights moved up to 14th on the NRL ladder following their 26-22 extra time victory over Manly Sea Eagles.