Robin van Persie hailed a "special day" after scoring for Manchester United against Arsenal, but refused to celebrate out of "respect" for his former club.
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The Dutchman needed just three minutes to remind the Gunners of what they lost when he quit the Emirates Stadium in a £24million deal in the summer.
The 29-year-old set up what proved a routine 2-1 win for United over their Barclays Premier League rivals at Old Trafford with his early goal.
Patrice Evra added the second after Wayne Rooney missed a penalty while the Gunners' misery was compounded by the sending off of Jack Wilshere, although Santi Cazorla hit a late consolation.
Van Persie told Sky Sports: "It was a special day, it was quite a game. I think we played well.
"We had a few chances, we should have scored two or three more but in the end we're happy with the three points which is all that matters."
Van Persie spent eight years with the north London club, culminating in last season's superb 37-goal campaign.
He has carried that form with him to United and his latest effort took his tally this season to 10 in 13 games.
The 29-year-old was taunted throughout by visiting fans but he did not antagonise them further by celebrating his goal.
He said: "I think it speaks for itself. I played there eight years and had a fantastic time there.
"I have respect for the fans, the players, the manager and the whole club."
United defender Rio Ferdinand said on MUTV: "He showed a bit more class than probably their fans did to him, but it is banter from their fans and he celebrated in the right way, I think."
United were dominant from the outset and could have won by a much clearer margin.
Antonio Valencia almost turned in a cross from Van Persie and the former Gunner forced two good saves from Vito Mannone, who was also tested by Rooney.
Manager Sir Alex Ferguson told Sky Sports: "It's unbelievable. The chances we missed, we really should have put it to bed a long time ago.
"You look at that scoreline, 2-1, you'd think it was a close game but it wasn't a close game.
"I think there was a lack of urgency in our game throughout, we were far too casual.
"It was an unusual Manchester United-Arsenal game. I know there was a lot of bookings but it didn't really get anywhere near the Manchester United-Arsenal games of the past.
"It was a strange game. I need to sleep on it."
Ferguson was also impressed by the performance of Van Persie.
He said: "It was an ideal start for Manchester United of course, and it was good for Robin in particular.
"I thought he was fantastic today, his movement and penetration were fantastic.
"I thought the back four did really well but after that, I'll just look forward to the next game."
Wilshere was booked in the first half and was fortunate to escape a second yellow card for a foul on Van Persie before eventually being dismissed for bringing down Evra.
Fearing something similar happening to Tom Cleverley, who was also on a yellow card, Ferguson withdrew his midfielder.
The Scot said: "I think Jack Wilshere was warned for his third foul on Van Persie then Thomas did a foul on Wilshere and I think he got warned.
"I wasn't prepared to take a chance and Anderson actually changed the game a bit for us."
England midfielder Wilshere had been in just his second match back after returning from a 14-month injury lay-off.
Arsenal manager Arsene Wenger said: "It was not deserved, he went for the ball.
"His game is commitment. I will have to see the game but it didn't look to me like he went on purpose over the ball."
Wenger added that he said "nothing special" to Van Persie when the pair met and claimed he was not concerned by the fact his former star player scored.
Wenger said: "Honestly that doesn't bother me at all. It doesn't matter.
"What you want is to win the game - you don't care about who scores in their team.
"What is most important is that you don't make a mistake at the back, and that you don't give chances away.
"I am disappointed of course, because we had a lot of the ball, but we were not very efficient in our final third or in their final third.
"Then you feel the domination was a bit illusionary - we had a lot of the ball, but they created more chances and deserved to win the game."