There has been a habit in recent years of players not celebrating when they score against their former side.
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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.
Forcabarca07
65
He was just a bench warmer so it's ok for him to celebrate..I guess even Madrid fans don't recognize him
beatbox
62
Disrespectful? Yes! But looking at the scenario at hand, I bet everyone would understand why he's so happy. Defeated European giant isn't a joke and no one ever thought a club like Ajax could beat Madrid 4-1 at the Bernabeu. I'm so delighted they qialified for the Quarters
Armstrongrno
53
Huntelaar went to Ajax for retirement and is already achieving more than he did at his time with Schalke.
herdsman
44
Huge fan of when players celebrate against their former sides. Even bigger fan of this level of celebration.
gentlem
40
There are players who refuse to celebrate out of respect to their former clubs and then there is Klaas-Jan Huntelaar 😀
FCBlahm
39
The fact he swung Marcelo’s shirt around and threw it around like it was meaningless. And then continuously being obnoxious with his celebration against his former club
KAUST
37
He wasn't celebrating against Madrid. He was cheering the travelling supporters. They also deserve some recognition