Man Utd-bound Amorim hails Guardiola as 'best coach in the world'
The Portuguese title holders face City in the Champions League on Tuesday in Amorim's penultimate match in charge of Sporting.
"(City have) the best team in the world and the best coach in the world," Amorim told Sport TV on Monday.
Manchester City beat Sporting 5-0 on aggregate in the last 16 of the competition in 2022 and Amorim said despite improving as a coach since then, there is still a gap between him and Guardiola.
"I feel like I'm a better coach (now), unfortunately what I feel is that Pep Guardiola has also become an even better coach, so the gap remains," Amorim told a news conference.
"Pep Guardiola was an inspiration to many of us coaches, as well as others."
City have won the Premier League four seasons running and record 20-time English champions Manchester United last won it in 2013, when managerial great Alex Ferguson was at the helm.
Guardiola lifted the Champions League with City in 2023 and has led United's rivals to six league triumphs.
Manchester United paid Sporting 11 million euros (£9.2m) to secure "one of the most exciting and highly rated young coaches in European football," they said after announcing Amorim's future arrival.
The Red Devils, currently 13th in the Premier League table, sacked Erik ten Hag a week ago before appointing the 39-year-old to try and bring the club back to their glory days.
'New Alex Ferguson'
Amorim led Sporting to their first league title in 19 years in 2021 and then won it again last season.
He said a defeat against City might even help reduce the inevitable pressure on him when he arrives at Old Trafford.
"If the result is very negative, expectations will drop and I don't think that's a bad starting point, when you begin at Manchester United," explained Amorim.
"If we win tomorrow, they'll think the new Alex Ferguson has arrived, which is very difficult to maintain.
"What matters to me is winning the game, having a good farewell in Alvalade (stadium), winning in Braga and then starting a new life in Manchester."
He said the Champions League clash in Lisbon will be heavily scrutinised because of his move to the north of England.
"I'm fully aware that I'm going to be judged as a manager on this game, and only on this game, and I realise what (people) can take from this depending on the result," added Amorim.
"Losing a game, especially to City, is not a failure."
Amorim will be in charge for one further league game after City, away at Braga on Sunday.
"We want to show that we no longer need Ruben," said Sporting captain Morten Hjulmand, hoping his team could rise to the challenge of losing their coach midway through the season.
"I felt sad when I heard that he was leaving me and Sporting, but in football opportunities like this arise.
"It's a normal part of the game, I hope he feels proud to receive such an offer."
