There has been a habit in recent years of players not celebrating when they score against their former side.
It started with a handful of bona fide legends not going wild when they bagged, and then drifted down as far as players who had only had brief spells at the opponents.
But whoever sent out the memo to the footballers of this world forgot to include Klaas-Jan Huntelaar.
Ajax overcame Real Madrid in incredible fashion on Tuesday evening, beating them 4-1 to advance in the Champions League.
And inevitably, their players, manager and backroom staff went mad after the game, with Edwin van der Sar and Marc Overmars being snapped doing so.
Footage has now emerged of Huntelaar doing the same, waving his shirt in front of the away end and celebrating with the fans.
He then walked towards the tunnel but took the opportunity to bask in the adulation of the fans again.
It comes as something of a surprise, given Huntelaar spent time with Real in 2009.
That said, he only spent half a season there, having joined them from Ajax.
And Ajax, who he rejoined in the summer, clearly means more to him, based on his celebration after the final whistle on Tuesday night.
The Dutch striker has now made it clear that he is not the sort of player who thinks think he should not celebrate against his old teams.
