North Melbourne's scintillating seven-goal opening term against Geelong was so good it was unsustainable, according to coach Alastair Clarkson.

The Roos are now officially out of the running for a wildcard spot, but threw the kitchen sink at the Cats in the first term, dominating the clearance count 22-5 before being overhauled by the older team and ultimately losing by 15.

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"We had a terrific start to the game, and the manner in which we played in the first quarter, strangely enough, was probably unsustainable for four quarters of footy," Clarkson said.

"Our contest and clearance work was (of a) real high quality, and while you want to maintain that standard for the whole game, it's just inevitable against a really good side that at some point in time they're going to arrest that significant advantage we had in that space.

"One of the things that Geelong have been really, really good at for the whole of this year, and for a long period of time, really, is getting the game played in their half. 

"Despite the closeness of the game, they still managed to control the ball well enough to have the game played in their half, much more than us, and while we were pleased we were able to score heavily once we got the ball inside 50, we just couldn't get ascendency in trying to control the game in that space."

North Melbourne's quest to hold off a fast-finishing Geelong was made tougher by a cheekbone injury to star Harry Sheezel, in an accidental second-quarter head clash.

"He's obviously a bit sore and sorry. He knew immediately he was in a bit of trouble. He'll get that checked out and scanned throughout the course of the week, but given the swelling around the eye and the bruising, it's pretty unlikely he's going to be available next week. 

"He was in a bit of pain and discomfort, but he had his wits about him. With the eye closed over and he couldn't see, then he couldn't participate in the game any further."