The Chile international has been settling into life at Old Trafford after having signed for the Red Devils from Arsenal in the January transfer window.
Sanchez headed to Manchester United as part of the same deal which saw Henrikh Mkhitaryan move to The Emirates.
It has been something of a slow start to life at Old Trafford for Sanchez, who has only scored three goals so far for Jose Mourinho’s men.
The 29-year-old is now set to line up against his former employers for the first time on Sunday when Arsenal make the trip to Old Trafford.
And Wenger has admitted it will be unusual for the Gunners to face their former player in the Premier League clash this weekend.
Speaking to Arsenal’s website, Wenger said: “At the time he did not accept our contract offer and the best possible way where we could get something from his departure was to make an exchange for the player of the quality of Mkhitaryan.
“For him, it was a move to another big club. Overall, both parties had interest to do what happened.
“Of course [it will be little bit strange to face Alexis]. The only thing that he has not changed is the colour, that’s still red.
“It’s strange for me to see him in a different shirt because he had a strong bond with the club and of course he was here for a few years. He did extremely well for us.”
Arsenal head into Sunday’s game on the back of their 1-1 draw with Atletico Madrid in the first leg of their Europa League semi-final tie last week.
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