THE INABILITY of Melbourne players to follow instructions allowed Magpies defender Adam Oxley to play free for most of the second half, according to Demons' coach Paul Roos.

Oxley took eight intercept marks among his 14 for the game and launched three Magpie scores from intercept possessions, with his performance turning the tide of the game when the Demons challenged.

Roos said the players were told at half-time to man up on Oxley when he was spare but failed to do so when he resumed in the role midway through the third quarter.

Click here to watch Paul Roos' full press conference

"That's why people don't want to be coaching, because sometimes they don't listen to you," Roos said.

"[Assistant coach] Ben Mathews has got a good saying [that] his dad used to tell him: 'Two ears and one mouth, listen twice as often as you speak'. [It was] something we spoke about after the game.

"An inability to listen was an issue. Obviously coaches need to do a better job explaining it."

However Roos argued that the Demons' poor ball use from the Demons was a bigger reason for the loss than their inability to cover Oxley.

"That [Oxley as spare] wasn't the difference in the game ... we kicked it back to them far too often," Roos said. 

Five talking points: Melbourne v Collingwood

The Demons conceded 12 of the Magpies 17 goals through turnovers and gave away one when defender Jack Fitzpatrick had a free kick awarded against him when he rushed a behind by throwing the ball between his legs. 

But Oxley was the post-game talking point. 

His influential game began when he took five marks in the latter part of the second quarter to steady the ship for the Magpies.

In a surprise move, Oxley began the second half on the bench but was picked up when he entered the fray and the Demons looked good, kicking four unanswered goals. The Magpies threw an extra man behind the ball in response and Oxley resumed his role as a spare in defence.

From that point on, Collingwood scored the final five goals of the game and Melbourne players seemed unwilling to respond to direction from the bench.

"After half-time they went equal numbers. [We'd] already been through it at half-time but weren't able to do it when they did it halfway through the third quarter," Roos said. 

"Our guys we ran through it but we couldn't get it done. Even when we did get it gone [we] just didn't get a contest."

Roos said he was disappointed with the Demon forwards' inability to compete after half-time as they had plenty of opportunities to compete in the air. 

The frustrated coach joked that he "saw a Sherrin hit a Boeing 737 at one stage and it still landed in (Oxley's) lap". 

Roos also pointed out that Demon utility Daniel Cross took five intercept marks when playing as a spare at various stages of the game.

The coach was heartened by periods of Melbourne dominance in the second and third quarters, describing that patch of the game where the Demons scored 10 goals to the Magpies' eight as equal to the best football they had played all season.

He also said there were positive signs from youngsters such as Angus Brayshaw and Jack Viney, and ideally the Demons would also be getting games into promising players such Dean Kent, Jay Kennedy-Harris, Christian Salem and Sam Frost who are missing due to injury.

"The guys that are learning to play the way we want them to play and there are some real positive signs," Roos said. 

Meanwhile, key defender Tom McDonald said he was "a bit angry" with his individual game on Collingwood's Travis Cloke in the opening quarter before he was moved off the power forward.

"I was embarrassed with my performance today, I was very poor," McDonald told Fox Footy on Monday night, citing Cloke's four-goal opening term.

"It was a poor game, in my head I was thinking way too much, it all was a bit of a blur and I almost felt dizzy out on the field. It was like the game was going around me and I wasn’t involved.

"This is the first time I've been comprehensively beaten all year and it frustrates me. I didn’t plan the day to go the way it did, but it'll take me a couple of days to get over."