He told his team last week prior to Saturday's clash against the Cowboys that they weren't going as well as they might think they are.

It was meant as a warning. A not so subtle dig to ward off complacency. He was worried about the pats on the back his team were getting after the best start to a season by a Knights' side in 18 years.

Unfortunately for the Knights coach, it went unheeded. Instead, all his players did for the opening 40 minutes in Townsville was do a good job of proving him right. The boom on them had been over-blown.

Just about all the parts of the game where they had earned rave reviews - defensive grit, resilience, commitment - there was little sign of any of it as the desperate Cowboys destroyed the Knights up the middle of the park to run in four unanswered first half tries.

Toohey's News: Listen to Barry Toohey's new podcast in your Podcast app

Remember, this was a side that had lost their past three games and conceded 99 points in doing so.

Coaches talk a lot these days about contact in defence. With the new rules in play promoting a quicker ruck, it's paramount players make their tackles stick to slow attacking momentum.

O'Brien preaches it every day at training. It's fundamental to the way he coaches.

A lot of it is attitude but there was little evidence of it against the Cowboys, whose big men were forever storming over the advantage line and quickly finding their feet against a back-peddling, ineffective defensive line.

The first half was almost like the Knights of old and it shone a light on how far this footy side has to go before it can consistently argue it is the real deal.

O'Brien admitted he was bitterly disappointed with his side's application and refused to use the game day travel as an excuse.

"I just think after the way the first set of the game panned out and their mistake at the end of it, we just thought this was going to be an easy day and we were wrong," he told the Newcastle Herald.

"They ran harder and tackled harder and just poured through us. They were more committed, more desperate, they wanted it a lot more.

"There needs to be some conversations individually and collectively about understanding where we are at and being truthful with ourselves and coming up with the necessary actions to fix it.

"We are definitely capable of it. We have shown it when we have had some fight there but we are not that team that can turn up with a six or seven out of 10 performance and get it done. We are not there yet.

"We need to be hungry every week and we have been for the vast majority of it but there's been a couple of occasions where we have just decided to dip our toe in at the start of games and ended up chasing our tails."

With Mitch Barnett and Connor Watson sidelined, O'Brien doesn't have much scope for making significant changes in the build up to next week's Manly game.

Centre Bradman Best will come straight back in, presumably for Gehamat Shibasaki and Tautau Moga, who was 18^th man on Saturday, must come under strong consideration. MIddle forward Tim Glasby will also have to be monitored.

He failed a HIA test and didn't return after leaving the field in the first half and it's not the first time he has suffered a head knock this season.

But O'Brien ruled out multiple changes.

"The guys out there are capable of it and if I just go and execute guys after a performance like that, they will never get better," he said.