"I thought we were really brave, tough and gritty, which is the performance we want to build our game, our Club, our town on."
The coach was extremely jubilant after his side earned a last-gasp and determined victory over the Warriors at McDonald Jones Stadium.
In pouring down rain and swirling winds, the match quickly became an attrition battle and was destined to go down to the wire.
A Brodie Jones try with four minutes to play handed the Knights an important two points.
Brodie Jones slides over to get Newcastle into the lead
"Tonight was worth the four points with the bye as we haven't had the bye yet," O'Brien said.
"I thought both teams were really brave in the conditions.
"I thought we completed really well going into the wind, and we hung in there really well and some of our goal-line defence was better than it has been in a long time."
O'Brien heaped praise on a number of individuals in a crucial victory for the red and blue.
Mitchell Pearce exhibited his class in his return game from injury, steering the side around the park and executing his kicking game.
Captain, Jayden Brailey was also in the thick of the action and competing on every play.
Highlights: Late Jones try sinks Warriors
"There was some massive moment by players tonight," O'Brien said.
"Jayden (Brailey) was involved in chasing down that line-break and stops the field goal. He's worth his weight in gold.
"We were a better team for having Mitchell out there.
"And we'll be a better team for next game by having him with this group at training next week.
"Brodie isn't a centre, we just chucked him out there this week, and he finds himself a try."
The coach also provided an update on the injured Kalyn Ponga.
The influential fullback is nearing a return and O'Brien says he's looking forward to having his first-choice spine on the park together.
"We'll take this week as it comes," O'Brien said.
"He's got a pretty thorough training program to get through this week.
"If he does all of that then I'm really confident that he will play in the next game.
"The longer we can keep this spine, and when wet get Kalyn back, get this spine playing and training together, we're obviously only going to get better and better.
"It's (going to be) a big end to the year for us."