Sanchez scored his first Manchester United goal against Huddersfield, prodding home from close range after missing a penalty.
And Mourinho was delighted at seeing the former Arsenal star get off the mark – particularly on his home debut.
“It was nice for Alexis Sanchez to win a match, the first at home,” the Manchester United manager said after the game.
“Nice for him to play well and show the desire and happiness in playing football.
“That is most important. It was not the goal of his dreams, but it is a goal.
Sanchez scored after both United and Huddersfield had impeccably observed a minute’s silence in tribute to the 1958 Munich Air Distaster.
And Mourinho feels it was important to mark the occasion with a win.
“It is important for the bad reasons (Munich air disaster) but the memories stay,” he said.
“The club looks at the date and event as a key moment in the history of the club. It is nice to do that playing at home and winning.”
Meanwhile, Nemanja Matic was also happy with the result.
“This win is good for our confidence and we have to fight ’til the end,” he said.
“Every game in the Premier League is a war. We have to stay focused until the end.
“Alexis Sanchez played really well and he will be a very important player for us with his quality. He is very good on the ball and does a great job defensively.”