It would have been easy for the Cats to consign that loss, which came after they led the Lions by 52 points in the third quarter, to "one of those things that happens in footy". Like North Melbourne and Melbourne probably would have done.
Not Geelong. So strong is its desire to effect change and exert a psychological power over every situation on a football field that that goal by McGrath has, ultimately, made the Cats an even better team.
The loss to the Lions was just their second of the year (they also lost to Collingwood by six points in round eight). But teams, historically, don't win flags when there are only six teams below them on the points conceded list, which was Geelong's situation the night of the McGrath kick.
Since that Gabba debacle, Geelong has strangled premiership fancy Fremantle, which it kept to just nine scoring shots. It restricted premiership favourite Hawthorn to a 10.12 (72) scoreline a week later and then on the weekend it allowed Melbourne just 19 inside 50 entries, an all-time low.
Try this for a transformation post McGrath goal.
In its first 12 games of 2013, Geelong averaged nine tackles inside it forward 50-metre zone (ranked No.13). In the three matches since, it has averaged nearly 24 (ranked No.1 in that period).
Contested possessions are even starker in contrast. Rounds 14-16 have produced an average of plus-27 (ranked 3rd) against opponents, whereas pre-McGrath goal, it was averaging minus-three (ranked 13) against opponents.
Hard-ball gets in rounds 14-16 have resulted in an average plus-13 (ranked third) over opponents. Until that point, it was minus-two (ranked 13th).
Geelong clearly identified a need to create more stoppages after the loss to the Lions, too. Up to and including the Lions match, the Cats were involved in 53.5 stoppages per game (18th). Since, they've averaged 86 (ranked first). We'll back our guys to win the ball at these moments, they obviously said after the Lions game. And they're right. They've gone from a minus-eight reading (ranked 17th) on clearance differentials to a plus-seven outcome (ranked fourth).
The ball is spending more time in their forward half, too. They were already ranked No.1 in this stat, with a plus-six minute outcome, but in rounds 14-16 it has been a plus-25 minute reading.
The Cats have conceded less inside 50s (37 against the previous 51, placing them No.1), and are allowing less scores per opposition inside 50 entry (37 per cent against 48 per cent, again placing them No.1).
Senior Geelong players Jimmy Bartel, Steve Johnson and Andrew Mackie in the past fortnight have all spoken publicly, when asked, of the need the club had to rectify several defensive parts of their game.
They were honest with where their team was in certain areas, and more importantly, along with their teammates, have gone out on a weekend and acted their way through those situations to ensure positive change.
We knew McGrath's kick was momentous for the Lions and their coach Michael Voss the instant it cleared the goal line.
Three weeks later, its impact is still being felt, and has clearly provided a resolve for a team which has won three premierships from the past six years to drastically alter its ways in order to go for a fourth from seven.
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