Months of speculation came to an end when former Barcelona star Sanchez joined United in a swap deal that saw Henrikh Mkhitaryan move to north London.
Wenger admitted that "uncertainty" in Arsenal's dressing room has disappeared following Sanchez's Old Trafford move.
Manchester United will be looking to book their place in the fifth round of the FA Cup when they take on Yeovil Town at Huish Park on Friday night.
Mourinho went onto praise the evolution of players like Martial before underlining the important of his front five - consisting of the France global, Rashford, Mata, Lukaku and Sanchez.
"We have set very high standards - winning three trophies in one season - but those are the standards I expect my teams to aim for", Mourinho added. "If the player one day are on the bench and don't like it, I am happy with that".
"I'm convinced that the way football is going, it's maybe not only to buy players with huge amounts of money, but have players in your team who care about your club, have a sense of belonging and a pride of belonging to the club".
"At the same time you need a combination with players like (Nemanja) Matic, Alexis - people that have experience in where we want to be - fighting for titles".
Smith, Legendary Frontman Of The Fall, Has Died Aged 60
In an interview with The Guardian newspaper in the autumn of 2017, Smith was asked about recent reports that he had passed away. In late December further U.S. dates were cancelled, with Vander citing "a full year of bad health" as the reason.
He expressed his desire to play in the Champions League but Arsenal stood firm and kept hold of him until this week.
City won't lose sleep over one transfer, however, and now lie 12 points ahead of their city rivals at the summit of the Premier League after 24 matches.
"I think it was a fantastic deal and it's only that if it's fantastic for everybody", Mourinho told reporters in his pre-match news conference.
As part of the FA's anti-doping guidelines, players are advised to notify the governing body if they are due to be absent from a scheduled training session. The good thing was is that it was 1-1 at half-time and we knew we could do better in the second half, and that's what we did.
"Could he perform better with us?" That's why I'm also happy for Mkhitaryan.
Cristiano Ronaldo has made the number seven shirt his own after first taking it at Manchester United.