0138 GMT March 30, 2020
The completion of the Sanchez deal was finally announced on Monday, with Mkhitaryan moving the other way after falling out of favor with Jose Mourinho at United, ESPN reported.
"We lose a world-class player and we gain a world-class player," Wenger said about the swap.
"How efficient will that be? That will be down to the performances of both players.
"Mkhitaryan has the qualities to integrate into our game and that is based a lot on movement and technical quietly. I think he has the attributes, a good team attitude as well and I'm confident that it will work. He can play in all kinds of positions – on the flanks and he can play through the middle as well. I think he's very versatile and it should help us to be very efficient going forward."
Mkhitaryan has only started one Premier League game since November 5 despite a strong start to the season, but Wenger said he is confident he can coax the best out of the attacking midfielder.
"I hope yes. I have no doubt about his attitude, his commitment, his desire to do well," Wenger said.
Sanchez will reportedly be the Premier League's highest-paid player at United, and Wenger said it was clear the financial aspects played a part in the Chilean's decision to make the move.
"I said here that he's 29 years old going onto 30 in 2018, and that it was maybe his last contract. Of course the financial aspect is important," Wenger said.
"He could combine both. I think he's going to a great club and he gets a great contract, so you can understand that a professional player can combine both aspects."
Wenger had long expressed confidence that Sanchez would extend his contract, which was set to expire this summer. But he deflected a question about whether the Chilean had actually come close to agreeing a deal last summer.
"Look, I don't want to come back on the history of his negotiations, but maybe one day," Wenger said.
"Alexis is a great guy and has always been committed, did the negotiations go well or not well? It has never affected him and I would just like to remind you I took him to the hotel on the night before the Crystal Palace game and he was completely focused and ready to play the next day until I told him, look you can go home, the deal is over the line. So, that's what he did.
"No matter how the negotiations went he was always focused on football."
Sanchez hit out at former Arsenal players who "cause damage" with their media speculation, and insisted he always gave 100 percent for the club.
Sanchez posted an Instagram message thanking Arsenal staff, teammates and fans on Monday after completing his highly anticipated move to United. But he also aimed a dig at pundits who have questioned his commitment in recent weeks.
"There are people (former club players) who have spoken with no knowledge of what happens inside the club and cause damage. I must say I always gave 100 percent, until the last day, when I asked to the Mister [manager] to be in the team, because I wanted to be a contribution."
Arsenal great Thierry Henry raised questions over Arsenal's team unity following the win at Crystal Palace last month, when the Sky Sports pundit highlighted how some players didn't celebrate Sanchez's first goal with the Chilean.
Sanchez didn't specify which former players he was referring to, but he referenced the French striker when discussing his reasons for leaving Arsenal.
"I remember today, a conversation I had with Henry, a historic Arsenal player, who changed club for the same reason and today is my turn," Sanchez wrote.
"Thanks for everything Gunners! All we achieved and the good moments that I gave to the club, I want to dedicate it to the fans, they are the most important. Thanks for every time you sing Alexis Sanchez Baby."