According to numerous reports, City's great rivals are prepared to pay the 29-year-old around £500,000 per week in wages, as well as other related bonuses, while the move looks set to cost £30m.
"I think clearly everybody knows that we are there and especially when Arsenal manager speaks so clearly like he did". "In this moment Mkhitaryan is our player, Sanchez an Arsenal player", Mourinho added.
Mourinho, speaking after United's 1-0 win at Burnley, said he expected the 29-year-old two-time Copa America victor to complete the move.
The Armenia global has been left out of the United squad which takes on Burnley at Turf Moor this afternoon, despite Mourinho insisting the former Borussia Dortmund playmaker was in a "good condition". "But [he is] in very good condition, training really well and in ideal condition like the others".
The Chile star was left out of Arsenal's squad for their 4-1 win over Crystal Palace on Saturday, with the forward reportedly having said his goodbyes to his team-mates late on Friday.
Mourinho did confirm Mkhitaryan will not be involved against Burnley on Saturday, however, despite being at full fitness.
And commenting on Luke Shaw, the Portuguese gaffer expressed his delight that the left-back is beginning to show his potential.
"He's a top player and to lose Sanchez is bad enough but if you lost Ozil as well, that bit of creativity, it would nearly be a mortal blow, a real kick in the teeth for Arsenal". That's hard. So that's why I made a decision to leave him out.
All that said and done this season although only halfway through, it looks more or less finished for the Emirates club but with some quality additions and some long-awaited departures the season of 2018-19 might just be the season Gooners are looking for.
"What I know right now is that he (Sanchez) is still an Arsenal player".
But with Zlatan Ibrahimovic still sidelined with a knee injury, Marcus Rashford was the only attacking player on the bench - a problem Mourinho says he hopes to solves by signing Sanchez.
Despite their slump, the Clarets have continued to exceed expectations in the top flight, but Dyche conceded the spending power of the top clubs is making it increasingly hard to do so. I know that the club is happy and the owners, the board are happy, they know I am happy and when that's the case one day we decide to do something we will do it easily.