Arsene Wenger has insisted that Robin van Persie would have fired Manchester City to the top of the Premier League just as he has done for United.

Arsenal host the champions at the Emirates Stadium on Sunday with Roberto Mancini’s side sitting in second place but trailing seven points behind their city neighbours.

That is largely down to the Dutch striker who left the Gunners in the summer for the Red Devils in a £24million switch and has already slammed in 20 goals.

Having come close to capturing Van Persie, City boss Roberto Mancini has been left with a sense of what might have been and has even admitted that the forward could be the key factor in stripping his side of their crown.

While it is highly unlikely that the Gunners will claw back an 18-point deficit and force themselves into the current two-horse race, Wenger admits he always knew his former charge would prove the difference in the title race.

Asked if it aggrieved him to see Van Persie doing so well for United, the Frenchman said: “No,” but added. “What is painful is to see Man United so far in front of us.

“You knew that when we sold Van Persie to Man United that that would be the case.

“He is one of the best strikers in the world and therefore you know he will score goals for them.

“He scored 30 for us in the league last year.”

Asked if the goal ace would have had a similar effect in a Manchester City shirt, Wenger said: “Yes.

“He’s at the peak of his game – 29 years old, going on to 30. He has gone through difficult moments in his career, he knows his game, he uses all his qualities in a very calm and intelligent way and he’s just at the peak of our game.

“You know at City they have other world class strikers. They have [Carlose] Tevez, [Edin] Dzeko, hopefully not [Sergio] Aguero [who will miss the game through injury], so they have the quality anyway.

“What would have made the difference if he’d have gone to City would have been one of another striker in a bunch of world class players.”