Sanchez finally completed his move to Manchester United with Henrikh Mkhitaryan moving in the opposite direction.
The Chilean had entered the final six months of his Arsenal contract and was determined to leave the Emirates after three-a-half-years in London.
And Wenger says the decision to allow Sanchez to leave made sense given his contract situation and the chance to replace him with a “world-class player” in Mkhitaryan.
He told Arsenal Player: “We move [him] out for free and in exchange Henrikh Mkhitaryan.
“We have a player who comes in on a three-and-a-half-year contract.
“So that means it makes sense on a negotiations point of view and secondly I believe that we’re replacing a very good player with a very good player, a world-class player with a world-class player.”
Mkhitaryan, 29, is unable to make his Arsenal debut in Wednesday’s Carabao Cup semi-final second leg against Chelsea.
But Wenger is delighted to have the Armenia international and believes he still has room for improvement.
He said: ”Mkhitaryan can play on the wing or in midfield, so I believe he can play very well in many positions.
“That can help us as well because he can play together with Ozil as well as playmaker, so overall it’s a good move.
“He’s a very complete player. He creates chances, he defends well, he can absorb distances and he’s very committed as well. I must say he’s a player who has all the attributes.
“Maybe where he’s a bit short is on goalscoring but he has improved that. If you look at the number of goals he’s scored in his career, it’s quite impressive overall.
“I’m very excited to get a player in who will be committed and focused. It is vital as well to have players who have experience, because we have a very good bunch of young players but we know that it’s not sufficient in the Premier League today to put them all in together.
“You also need a good weight of experience in your team and he will contribute to that.”