Gunners supporters were furious when Van Persie was allowed to join Alex Ferguson's side in 2012 at a time when he was the Premier League's top striker -- and became even more frustrated when the Dutchman fired United to the title the following season.

Sanchez is now set to make the switch to United as well after refusing to sign a new deal at Arsenal, with Henrikh Mkhitaryan expected to move in the other direction. But Wenger isn't expecting the same kind of backlash over this deal.

"I would say that our fans today know that Sanchez will not extend his contract, and they have accepted that idea," Wenger said. "And the fact that it will not be one-way traffic, it will be other-way traffic as well [with Mkhitaryan], so that makes the whole thing a bit smoother maybe, a bit less disappointing. We lose a player yes, but we could gain another player of top level as well."

Wenger acknowledged that there is a risk in letting Sanchez join a direct rival as he could well replicate Van Persie's heroics in leading United to the title next season. But even the Arsenal boss himself seemed to suggest that the Dutchman's exit hurt more than Sanchez's will.

"We took Van Persie when he played in the reserve team at Feyenoord and we [put in] long work with him. And when you get them there to the level and after they leave, of course that is the most painful," Wenger said.

"After, that they do well for the other club -- you know that they will do well. But most of the time it's after long, patient work that you have done with the players. ... You forget that Man United had already a very strong team [when Van Persie left], and they have as well a very strong team now. So was it him on his own that made a difference? I don't know, but he was a great player, Van Persie."

Wenger told a news conference earlier on Thursday that the Sanchez-for-Mkhitaryan swap is "likely to happen" before Saturday. While reports have claimed Mkhitaryan has been holding up the deal over concerns about his wages, Wenger said the drawn-out nature of modern transfers is because of the number of lawyers involved.

"Today you make the negotiations happen and after that it's basically a lawyer's battle. Because every point is analysed and scrutinised," he said. "The lawyers need to deserve their money, so what was before a handshake -- 'OK you do it' -- today takes longer."

The Sanchez deal has raised eyebrows because of the amount of money that United has offered the Chilean in wages and a sign-on fee, with Wenger saying players will increasingly run down their contracts to seek deals where they pocket the transfer fee themselves instead.

Asked if he could see a player earning £1 million a week, the Frenchman replied: "How many weeks do you have in a year, 52. You cannot rule anything out.

"Who was the first player who was a £1 million transfer? Trevor Francis [in 1979]. Today it looks ridiculous.''

And he said Arsenal may have to re-think their future transfer policy as a result and possibly return to the strategy of unearthing young talents rather than ready-made stars.

"We have to revisit the way we structure our club and our scouting policy," he said. "You look at the players now, the world-class players, you look at Ronaldo, Neymar, Sanchez, their level of financial demands and the level of their costs. We have to go younger.

"Certainly these players are not affordable. [Finding young talents] is more difficult nowadays because the competition everywhere is very big. But what is important today is that we are maybe the club that give them a chance more