Running out of space, Petrie threw the ball onto his right boot and celebrated with Harvey as it split the middle post high to seal a memorable 21-point win.
IN ROUND seven this year, North Melbourne had just been handed its fifth loss for the season and was 15th on the ladder.
There had been one win so far - the week before against Port Adelaide - and the loss to Geelong at Skilled Stadium by 66 points was a terrible way to follow it up.
The Roos won the next week, against Melbourne by 41 points, but then the world caved in once again.
They lost two winnable games - to the Brisbane Lions by 14 points and then the Sydney Swans by a heart-breaking one - and they took their tally of games lost by less than three goals to four for the season.
Then something changed.
The Roos beat Adelaide, easily, by 47 points at Etihad Stadium. They backed it up against Gold Coast the next week and won by 59 at Metricon Stadium.
On Saturday, against Essendon - a team that was third on the ladder with five wins and one draw after round eight - they won again, this time by 21.
They led all afternoon, by as much as 25 points in the first quarter, 31 in the second and 20 in the third before the Bombers - relentless and undermanned with two players out of the game injured - hit the front early in the final quarter.
Drew Petrie, one of their more experienced players, admitted afterward that was the point of the match where the Roos as recently as this season might have packed up and gone home.
"We lost a few games to sides we were in front of for a lot of the game and then allowed to run over us," he said.
"We've just got a bit more fight in us now. Essendon were coming hard and the crowd were roaring, and I guess a lesser side might have rolled over and let them win, and we might have been that side six weeks ago.
"Now, I think we've got a lot more belief in ourselves and we've got a really even contribution from all the boys."
The Roos kicked the last four goals to win by 21 points. It was their third triumph in a row, but first where they'd emerged after being really tested late in the game.
Petrie says belief created from the past fortnight influenced the resilience and fight the Roos showed, while coach Brad Scott believes the explanation for why his side is suddenly knocking on the door of the eight is much simpler.
"I always say that people think that it's something you drastically change and things turn around when really, we've just been working hard on the fundamentals of the game," Scott said.
"We knew from the things we look at closely we weren't far away; we just had to add a bit more polish to our game.
"I'm under no illusions that Essendon had 30 scoring shots to our 26 so it's nice to sit here in victory when we kicked accurately and the opposition didn't.
"They had their chances to win the game and didn't take them, and that's been us at various stages throughout the year."
Scott said the improvement of the side had been constant in the coaches' eyes, and it was now starting to be witnessed by all in basic the basic win-loss count.
Petrie said the inclusion of players like Levi Greenwood and Ryan Bastinac and the return of Nathan Grima after a finger injury - and with the trio "holding up their end of the bargain" - had helped immensely.
But he says the side's improvement in recent weeks can also be attributed to something more than just personnel coming into the side.
"We've grown up as a group," he said.
"We've played that little bit longer together now and we're getting used to the way we play and now we know what works for us.
"When we do that and we're predictable to each other, I guess you see what happens with the final result.
"Maybe in the first six week of the year, we had a few teething problems and we weren't playing to exact instructions.
"That was a possible reason but now I think we're following Brad's instructions really well and we know what each other is doing."
