Amorim enjoyed the perfect send-off from the Jose Alvalade Stadium on Tuesday as his Sporting side came from behind to thrash City 4-1 in his final home match before taking charge at Old Trafford next week.
The 39-year-old will come up against City again in a Manchester derby in little over a month's time, but he does not think Sporting's remarkable Champions League triumph will have any bearing.
"This doesn't mean anything in particular," said the Portuguese, who will officially leave Sporting and head to Manchester after their game at Braga on Sunday.
"It's misleading. We cannot transport one reality to another context. Man Utd cannot play the same way we do. We will have to adapt.
"When I arrive in Manchester I will be living in a different world with a different starting point.
"This was a one-off and we had luck on our side. I will take this to the Premier League, but it will be different in Manchester. It will be fun and I am ready for the challenge."
Sporting looked like they could be in for a long night as Phil Foden opened the scoring inside four minutes and City created numerous other chances in the first half.
The game turned after former Coventry striker Viktor Gyokeres - linked with a move to Amorim's United - broke away to equalise just before the break.
Maximiliano Araujo put Sporting ahead early in the second half and Gyokeres went on to sink the visitors by completing a hat-trick with two penalties, although City's Erling Haaland did miss a potentially pivotal spot-kick.
Amorim had quipped before the game that he would be built up as the 'new Sir Alex Ferguson' if he beat City, but he was quick to play that down and insist he would not be reading any media reports.
He said: "I was playing with words when I said that, it was a joke.
"I am not going to read anything for six months. I did this when I came to Sporting and I will do it again.
"The only way I can do my job is to work and focus on the team.
"With City missing their penalty, everything went very well for Sporting."