Florentino Luis is the Benfica youngster with a €100million (£90m) release clause who is said to be a target for both Manchester clubs.
The 20-year-old only made his senior debut in February but already there is talk of a big-money move to the Premier League.
Here, we take a closer look at the defensive midfielder courting the attention of Europe's biggest clubs…
What type of player is he?
He occupies a deep-lying midfield role but has the legs to get about the park, as you would expect of one so young.
That he has already earned the nickname 'The Octopus' tells you a lot about his strengths, legs so long that he can nick the ball with ease and authority.
Comparisons have been drawn with Chelsea and France midfielder N'Golo Kante, although at 6ft Florentino carries a more imposing presence.
Like Kante, he has an ability to break up play and spring quick offensives for his own side. He has scored once from 18 appearances, but that is not to say he does not have an eye for goal and he isn't afraid to take aim from range.
He spent his early years playing Futsal, so his touch and technique is second nature.
How can it be that after 18 games he is so highly rated?
The fact he has emerged at Benfica has a lot to do with it. The Portuguese club are among the best in the world at producing young players - look no further than Joao Felix, the teen sensation who joined Atletico Madrid for £113m this summer.
So, naturally, scouts are monitoring every debutant. Florentino made his in February after promotion from Benfica B having spent nine years in the club's youth ranks.
But it is his performances above all else which have attracted the attention and, to win a regular starting spot so soon, serves to highlight how good he has been, especially given his influential role in Benfica's title win.
Is he a full international?
Not yet. He is of Angolan descent but was born in Lisbon and has been capped by Portugal at every youth level, where he has won both the Under-17 and Under-19 European Championships.
Promotion to the senior ranks alongside Cristiano Ronaldo surely awaits in the coming months and that, you suspect, would not be a problem for a player whose maturity belies his tender years.
Where would he fit in at United and City?
Florentino actually carries an uncanny resemblance to Paul Pogba and, given his discipline in a midfield holding role, the pair would probably make for a decent partnership.
At City, Pep Guardiola will be looking at Florentino as another option in the defensive midfield position currently occupied by Rodrigo and the ageing Fernandinho.
How much would he cost?
His release clause is set at around £90m but there is talk of offers in the region of £65m perhaps being enough to do a deal.
That, though, will depend on his progression this season - and it could well be that £90m looks cheap come next summer.