Arsenal manager Wenger allowed Van Persie to be sold to Manchester United last summer, in a lucrative £24million deal which City boss Roberto Mancini believes swung the balance of power back to Old Trafford.
However, the French coach believes the way United have pulled clear this season is not simply down to the contribution of one player - and highlighted the narrowest of margins by which City had become champions on the final day of an extraordinary campaign last May.
"You can say that Robin had an impact, but the other teams are not as close this year like Man City, who were always top last year. This year it was one-way traffic," said Wenger.
"The difference is that City has dropped off.
"United lost only on goal difference last year and if QPR did not know that they were safe, they (United) would have won it last year.
"The game (against Manchester City) finished later. They (QPR) knew they were safe in added time.
"Don't you think that they knew?
"It is a kind of relief and could have contributed to the fact that they lost in the final two or three minutes."
A personal phone call from United boss Sir Alex Ferguson to Wenger helped push through the deal for Van Persie.
The Arsenal manager, however, is adamant the club was put in an almost no-win situation because the Holland international did not want to sign a new deal.
"The real issue was that Robin had only one year to go and he didn't want to extend," said Wenger.
"You would face the same problem this year. Even if he had an exceptional season, he would be free, he will go somewhere else - and then people still say, 'why did you let him go'?"
Arsenal trail United by some 21 points heading into the final four matches of what has been another frustrating Premier League campaign chasing Champions League qualification rather than mounting a long-overdue sustained title challenge.
Wenger, though, insists the club have far from been standing still in their quest for a first trophy since the 2005 FA Cup.
"First of all, what we have managed during this period is not finish 12th or 16th in one season. We have always been in the top four," he said.
"If you read the statement of John Terry when they played in the Europa League, he came out and said, 'there is only one thing that matters for us - to finish in the top four', that shows you that is a real target.
"We have always been in there, and we also have been in the final of the Champions League without losing a game during that period.
"Yes, we missed something, we were short a few times to win the title during this period, but I am sure we will be back again."
Wenger added: "The only way we can deal with that is to come back next year and win it, but the competition is very hard now.
"We said before that Chelsea would be stronger and everybody would be stronger - so let's make sure that we are stronger too."