COLLINGWOOD midfielder Ben Johnson admitted he was physically spent by the end of Saturday's 75-point win over Port Adelaide, but believes the Magpies will quickly adjust to the three-man interchange bench.

Johnson said he felt the effects of the new rule in the final quarter against the Power after spending more time on the ground than usual.

However he believes the Pies have the ability to adapt to the reduced bench with their high level of fitness, which is boosted each year by their pre-season training camp in Arizona.

"It's definitely a little harder on the body; you don't get to go off as much but we'll get used to it," he told collingwoodfc.com.au after the game.

"I didn't get to go off too much but that's the way it's going to be. I normally go off a bit more; it depends where I'm playing.

"I was feeling it in the last quarter but that's every year in round one. You go through the NAB Cup games and you feel okay but the intensity picks up and the time picks up.

"It's going to be a little bit harder but I'm sure we'll be fine and get through it because we're pretty fit."

The Magpies had the game in control by the end of the second quarter with a 58-point lead as the siren neared.

However, a tenacious Port fought back to within 16 points in the third quarter, with five straight goals getting them in the contest.

"In the second quarter I think we were just a little bit lazy and just didn't play our game," Johnson said.

"When we don't do that, teams will come pretty hard at us.

"When we're on top we usually stay on top but it didn't happen and to the boys' credit, when they did come back at us, we piled on a few goals to get us back up there."

The Pies boasted three new faces to their 2010 premiership side, with Chris Tarrant returning from Fremantle and Andrew Krakouer and Simon Buckley making their debut for the club.

Johnson said the importance of the three players, particularly Tarrant in the wake of the season-ending knee injury to Nathan Brown, was huge.

"Taz is going to be great down there, Krakouer is just going to get better week by week and Bucks has slotted in well down in defence," he said.

"Bucks was there last year and he didn't play; he was close a few times and he really worked hard over the pre-season, got his chance in the NAB Cup and there he is."

Tarrant had a quiet day after starting alongside Jay Schulz, who sustained a knee injury in the second quarter, while Buckley showed promising signs across half back before sneaking forward for two goals.

Krakouer had 19 touches and five inside 50s, and while he kicked just one major, he set up several shots at goal.