When Robin van Persie gave Manchester United the lead in the 27th minute against Arsenal he turned and celebrated like he had played for them his entire career.
The reality is it was only August 2012 when he joined United, for £24million.
It was Arsenal he left, having worked under Arsene Wenger since his 2004 arrival.
Refreshingly, his celebration represented one of the few instances in recent years in which a player has been prepared to show his passion for his current employers against a former team.
Cristiano Ronaldo, Jimmy Floyd Hasselbaink, Shaun Wright-Phillips, Adam Johnson and Curtis Davies are just a handful of those who did the opposite.
In the instances of Ronaldo and Hasselbaink, who did much over several years for United and Chelsea respectively, it was perhaps understandable.
For the others, however, that simply wasn't the case and represents one of the most frustrating habits of the modern footballer.
Van Persie was outstanding for Arsenal, as he now is for United. His decision to celebrate also represents a change from last season, when he refused to do so during April's 1-1 draw at the Emirates or last November's 2-1 win at Old Trafford.
'I played there eight years and had a fantastic time there,' the striker said at the time of his refusal to celebrate. 'I have respect for the fans, the players, the manager and the whole club.'
It's right that this time he showed all of his passion.