Chilean worldwide Sanchez will sign for Man United on Monday or Tuesday after undergoing a medical at the club's Carrington Aon Training Complex on Sunday afternoon.
Mkhitaryan, meanwhile, has been in London over the weekend to finalise his transfer to Arsenal.
The Sanchez and Mkhitaryan transfer has been the story dominating all the headlines over recent days, and both players have travelled to their prospective new clubs today to have their medicals, meaning the deals should be finalised within the next 24-48 hours. 'I think it is so close.
"No disrespect to Mkhitaryan because we have only seen glimpses but in terms of Arsenal, is he what Arsenal needs?"More news: Key Arsenal duo to sign new deals?
Both clubs benefit, there is little doubt about that.
Arsenal have also made an enquiry about Borussia Dortmund striker Aubameyang, according to the Bundesliga club. That's in return for a layer who was always going to leave in five months time, and was likely to leave this month anyway.
He is expected to sign a four-and-a-half-year deal with Man United.
The deal has generated a huge amount of interest with Manchester City, Chelsea and Liverpool all being linked with moves for Sanchez, and supporters are also beginning to find the in-depth coverage rather amusing.More news: Russian Federation tells United States to show proof of N. Korea sanctions-busting
Sanchez was out of contract at Arsenal this summer and could have left for nothing.
Mkhitaryan is an incredibly versatile player and probably one of the best options on the market to replace Sanchez.More news: Natalie Portman, at 13, experienced 'sexual terrorism'