CARLTON coach Brett Ratten says his team won't be distracted by the tightness of the race for the top four in the lead-up to the finals.

With their 18-point win over North Melbourne at Etihad Stadium on Friday night, the Blues moved six points clear of the West Coast Eagles, ensuring they'll remain in the coveted double-chance position for at least another week.

Although Carlton can scarcely afford to drop a game before September without risking a fall to the lower half of the eight, that's not something the coach wants his players to spend time worrying about.

"We can only control what we can control, so we'll just push ahead and keep making sure that we get our game right," Ratten said after the win over the Kangaroos.

"We get 22 games to rehearse what we want to put in place with that great opportunity of being one of the eight teams in the finals.

"So this was another chance to rehearse what we want to get out of the season and the things we want to put in place to make sure we improve with every performance."

If this was indeed a "rehearsal", Ratten admitted that there are still some things to work on before opening night.

The Blues were wasteful from set shots, failing to capitalise on the amount of possession in their forward half of the ground.

They also allowed two first half North Melbourne 'coast-to-coast' goals from kick-ins.

Combined, those lapses added up to an 11-point half-time Carlton deficit despite a 26-16 lead in inside 50s.

"I thought our kick-in work was really average on the defensive side," Ratten said.

"We corrected it after half time and it looked a lot better.

"But that cost us two or three goals up to half time. We don't want to do that again, because the game could slip away very quickly if you do that."

Ratten also revealed he'd used his suspicion that North Melbourne fancied its chances against the Blues as a motivator for his players.

"For our football club it was time to make a stand," Ratten said.

"We spoke about, 'why do the Kangaroos pick us for their Friday night game every year?'

"They asked for us. Is that because we're close geographically together or do they think it's a great way to spend their Friday night that they get from the AFL?"

The coach reported no major injury concerns from the match.

Dennis Armfield hurt his ankle during the third quarter and was subbed from the game at three quarter-time, but Ratten said the problem wasn't serious.

"He probably could have pushed through, but he just had a couple of sprinting efforts that weren't at the top of his game, and I thought it was time for Ryan (Houlihan) to come onto the ground and get involved," he said.