Amorim arrived at Man United last week and he will be on the touchline on Sunday after succeeding Erik ten Hag.
He will take the place of Ruud van Nistelrooy who steadied the ship on an interim basis after Ten Hag's sacking.
Amorim has developed a reputation as one of Europe's hottest coaches after guiding Sporting Lisbon to two league titles in four years.
The former Portugal international was linked with the West Ham vacancy during the summer and travelled to London for talks.
He ultimately rejected the Hammers' offer and apologised to Sporting fans for taking the meeting.
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Amorim was considered by Liverpool, Barcelona, Bayern Munich, and Juventus but all clubs ultimately decided to go in different directions.
The 39-year-old was also identified as a potential successor to Pep Guardiola at Manchester City.
But he's arrived at Old Trafford now and here's what can United fans expect from him...
Amorim: A Brief History
Amorim spent a brief period coaching at Casa Pia, then a third-tier club in Portuguese football, after his retirement from playing.
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He was appointed as Braga reserve boss in September 2019 but handed the reigns to the first team within four months.
His start to managerial life at the top level in January 2020 began with a 7-1 destruction of Belenenses and a trophy soon followed.
Before the end of the month, he'd overseen a League Cup final win over Porto and soon went on and to claim wins against the rest of 'Os Tres Grandes' - the big three.
This included Braga's first win away to Benfica in 65 years following a goal from Bayern Munich and former Fulham star Joao Palhinha.
The remaining side in Portugal's big three had seen enough - Sporting forked out the third-highest transfer fee for a manager in history by splashing €10million (£8.3m) for his services that summer.
Despite his inexperience, Amorim soon rewarded that faith in kind by delivering the club's first league title in 19 years.
Sporting were crowned champions again in the 2023/24 campaign, with Amorim also delivering two Taca da Liga titles.
He currently has the club sitting first in the Portuguese top flight so far this season thanks to a 100 per cent record from nine games.
Sporting are also eighth in the Champions League league phase table with two wins and a draw from their opening three fixtures.
Style of play and tactics
The Portuguese manager has a clear preference for a 3-4-3 formation focusing on high pressing and possession.
Amorim typically attacks in a 3-2-5 shape and then defends as a 5-2-3 - radically different to United's system under Ten Hag.
His absolute commitment to his playing philosophy was reportedly among the reasons proposed talks with Liverpool broke down.
Amorim oversees possession-based attacking football, but there is a pragmatism to his tactics as well that focuses on defensive structure.
United often lined up in a 4-2-3-1 shape under Ten Hag but criticism remained that no clear style of football was on show.
In contrast, Amorim has adapted his 3-4-3 formation so that every player has clearly defined roles when in and out of possession.
He first deployed a back-three in ironically his third-ever game as a manager at Casa Pia, having lost his first two.
The switch in system brought instant success and has since been his favoured set-up at Braga, and then Sporting.
Amorim's sides are typically flexible between playing in a low block - (a compact defensive shape focused on protecting the space close to goal) while aggressively pressing when out of possession.
What is more constant is that in his 3-4-3 formation, attacking wing-backs are key in all thirds of the pitch.
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Amorim has used two defensive midfielders to cover for his wing-backs - who push high up the pitch and stay wide to form a 3-4-2-1.
This also allows his two attacking midfielders to drop into pockets behind a lone striker while still stretching the opposition's backline.
The close proximity of teammates in and around the centre-forward also allows Sporting to go direct, with passes into Viktor Gyokeres.
The latter then holds it up before laying it off, with the position of the high wing-backs also leading to regular switches of play.
How might this work for Man United?
talkSPORT.com has taken a look at how United could set up under Amorim if he has a fully fit squad.
He won't have everyone available for his first game, as there are some injuries, but this would be his dream scenario for the Red Devils.
Amorim is known for championing youth and can implement the high-pressing, possession-based style of football INEOS are after.
Like Ten Hag, he intends for his goalkeeper to be active in the build-up phase, with Andre Onana's ability on the ball vital.
In possession from a goal kick, the central defender of Amorim's back three will join the midfield line at the tip of a diamond.
That three-man midfield creates better passing angles for Onana and his remaining two defenders to work the ball wide and get forward.
His starting back three would likely consist of Matthijs de Ligt, Lisandro Martinez, and Leny Yoro - with Harry Maguire also comfortable using that system when fit.
Manuel Ugarte flourished under Amorim at Sporting and will relish returning to his role as the defensive shield of a double pivot.
The Uruguayan will be joined by one of Kobbie Mainoo, Mason Mount or Christian Eriksen to provide the creativity in possession, but Casemiro offers an older head if needed.
On paper, Amorim's system doesn't operate with a No.10 but his compatriot Bruno Fernandes would likely start from the right.
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But, as mentioned, the key to Fernandes dropping into central areas behind Rasmus Hojlund will be the overlapping wing-backs.
Diogo Dalot or Noussair Mazraoui will compete for that spot, with Alejandro Garnacho vying with Amad Diallo and Marcus Rashford in the final third.