North Melbourne came out firing at Etihad Stadium on Friday night, outscoring the Magpies 6.5 to 2.2 in the first term.

The Pies fought back and came within 16 points of the Roos in the final term with goals from Sidebottom and Alex Fasolo, but North again pulled away to win by 40 points.

In his post-match press conference, Collingwood coach Nathan Buckley slammed his players for not trying hard enough in the first quarter.

But Sidebottom insisted the Pies players had been enthusiastic and ready to go from the start of the game.

He said they knew North would be fired up, after a five-game losing streak had seen them fall from first to eighth position on the ladder.

"We knew what were up against but we just couldn't match it," he said.

"The boys were up and about and I think we trained well during the week, but when push came to shove we just got outworked."

Adelaide outscored the Pies 5.2 to 1.6 in the first quarter last weekend and went on to beat them by 28 points.

Collingwood beat GWS in round 16, but the Giants still won the first term 7.2 to 3.2.

Sidebottom said he did not know exactly why his team was failing to start well.

"If I knew I'd be solving it," he said.

"They were just better than us, [our] centre clearances were down, they were giving their forwards first use and it was hard for our backs to defend," he said.

"At the same time we didn't use the footy very well and made it hard for our forwards, so it's probably a combination of a few things."

Collingwood fans booed North Melbourne small forward Lindsay Thomas during the game, over the perception that he ducks when tackled in order to be awarded a free kick for high contact.

Thomas was in blistering form on Friday, ending the game with five goals.

Sidebottom said he was not concerned about the way Thomas played.

"If he is smart enough to draw a free kick, then good on him," he said.

"If you ask any player, if you do something that the crowd or anyone doesn't like, if they get a free kick I'm sure every player's going to do it."

Collingwood will play the West Coast Eagles at the MCG on Saturday afternoon.