The coach watched on as his team went into the halftime break at 30 points to 6 down, before managing to slow the blue and gold down during the second half.
An incredibly poor defensive effort from Newcastle saw the Parramatta middle forwards have their way, while Clint Gutherson and Mitchell Moses dominated a contest that was one-way traffic from the outset.
Ultimately, Parramatta wound up with over 600 more running metres, a line break count of 13-3 (that was 9-0 at one stage), an offload victory of 16 to 7, and the Knights finished up with an incredible 61 missed tackles in a game they were never in.
O'Brien, speaking at his post game press conference, admitted it was a horrible performance, but refused to outright slam his team, instead suggesting on-field and off-field factors contributed to the loss.
"I didn't see it coming. It was a horrible performance, let's be honest, but they haven't been horrible, so I'm not going to kick them to death either," O'Brien said.
"I think it has been a really big month on-field and off-field. There is some stuff going on there that you'd know about. Obviously, losing Brails [Jayden Brailey], and they are going to sound like excuses, but I don't care if they sound like excuses.
The Knights had been involved in a golden point clash a fortnight ago against the Penrith Panthers, before playing out a narrow loss to the North Queensland Cowboys in Townsville last weekend, with a physical encounter going down to the wire.
A six-day turnaround did them no favours in their trip to Parramatta, and O'Brien said that the Cowboys performing similarly last night in a thumping loss to the Cronulla Sharks helped paint a picture of why the Knights were so poor.
"The team have been working pretty hard for a month, so there is that part of me," O'Brien said.
"I watched last night's game [between the Sharks and Cowboys] and I thought last week's opposition [the Cowboys] showed the same signs, and we have had two golden points before that, so I'll give them a bit of an out there."
O'Brien said the team hadn't suddenly lost their ability to defend, and instead, a long campaign had caught up with them.
"We just started, our defence, we were quite loose through the middle. We have been defending really well, and we haven't lost that ability in six days, but we have lost the ability or the gas in the tank. We need this bye. It's been a long campaign," he said.
The Knights have conceded just 34 points over the last fortnight leading into their clash against Parramatta, although struggled defensively at times earlier in the season, letting in 32 against the Manly Sea Eagles and 36 against the Dolphins.
O'Brien's side will now miss Magic Round with the bye, before waiting until the following Sunday - a 16-day turnaround - to play the Gold Coast Titans at home in Round 11.