Arsene Wenger said before Sunday's visit to Old Trafford that he would always think of Robin van Persie as an Arsenal man.
Whether the Frenchman still feels that way, having watched his former striker's jubilant celebrations after scoring the winner in Manchester United's 1-0 triumph, remains to be seen.
Van Persie followed up his header by racing away in open-mouthed delight, skidding to a halt on his knees and being swamped by team mates.
Then, fists clenched and arms raised, he turned to the home fans and let off some more steam.
It was hardly the gesture of a player missing North London, any more than it was likely to mend broken fences with Arsenal's travelling faithful whose colourful chants had been far from complimentary.
"Eight points clear, Robin," they had called out, but by the end of the match it was only five and United were back up to fifth place in the table having ended Arsenal's run of 15 unbeaten away games in all competitions.
The match was seen as a big test of Arsenal's mettle, and of United's championship credentials at the start of the post-Alex Ferguson era, and Van Persie delivered his own verdict.
Sold by a reluctant Arsenal to United for 24 million pounds ($38.39 million) in 2012, he has made a point since then of rubbing in just what Arsenal let go - and are still missing up front - every time he plays against them.
Sunday's 27th minute header, his seventh league goal of the season, kept up the Dutchman's record of scoring in every match against Arsenal since his departure - with three goals in three games.
Last April he returned to the Emirates with the champions and was clapped on to the pitch by the Arsenal players in a guard of honour. He returned the favour by scoring from the penalty spot in a 1-1 draw.
In November, he netted in a 2-1 win at Old Trafford but was more restrained in his celebrations.
"I took him when he was a very, very young player. We have gone together through very difficult periods and he became a world-class player and for me he is an Arsenal player," Wenger said last week.
Van Persie's new boss David Moyes will not be paying too much attention to that.
"This was a big result for us today. Arsenal have been in terrific form this season and we had to play well today to get the result," he told Sky Sports television.
"I thought we started the game well, we were very good in the opening 20 to 30 minutes. I thought in the end our whole determination, of effort, commitment, good play, helped us in the second-half when we were under more pressure."
Wenger was disappointed to concede from a set-piece.
"I felt in the first half we were too nervous and rushed our game too much and lost too many balls. Second half when we played composed, and played our usual game, I felt we were very close many times to scoring.
"It didn't happen. We have to digest that and come back after the break in a strong way."