Embalo, 16, is regarded as the brightest young prospect to emerge from the Benfica academy in recent years and United have been credited with serious interest in bringing him to England while his star is still on the rise.
The Premier League giants dispatched chief scout Javier Ribalta to watch over the teenage winger when Benfica and United's youngsters met in the Uefa Youth Cup last October, with subsequent reports in Portugal claiming a deal had already been struck between the two clubs for the Guinea-Bissau-born Portugal youth international.
Embalo's agent confirmed a meeting between United and Benfica over the youngster did take place, but stressed no deal was done, with clubs across Europe closely following his progress.
Barcelona are among them, with Marca reporting in December the Catalan giants have been following his progress for "several seasons". Sporting director Robert Fernandez is now paying particular attention to his rise in Portugal.
RB Leipzig are another side to have been watching over his progress and appear close to beating Europe's elite for the youngster's signature.
According to Portuguese publication O Jogo, Leipzig have already seen a €13m offer for the player, who is still to make a senior appearance for his club, rejected by Benfica president Luis Filipe Vieira. The Bundesliga club will raise that offer to €18m with Leipzig's sporting director Ralf Rangnick in Lisbon this week to wrap up the deal.
Leipzig hope the promise of a quicker route to their first-team will convince Embalo to choose their offer.
Real Madrid have also been closely linked with the teenager in the past and it was rumoured back in May that they were willing to pay up to €15m in order to beat a number of other high-profile European suitors to his signature.