Jose Mourinho's men secured a narrow 1-0 win against the Portuguese giants at the Estadio da Luz in the Champions League on Wednesday evening.
Earlier in the day United went toe-to-toe with Benfica's Under-19s in the UEFA Youth League, with the feisty encounter ending 2-2 at the Caixa Futebol Campus.
Javier Ribalta, one of United's chief scouts, was among the interested observers in Seixal, where Embalo came on as a 65th-minute substitute.
While unable to make much of an impression on Wednesday afternoon, Press Association Sport understands the 16-year-old is being closely tracked by the Reds.
Embalo has caught the eye of United but Real Madrid are also reportedly keeping tabs on the Portuguese forward
It is understood United have also been impressed by attacking midfielder Joao Felix
A slick player in the ilk of fellow Benfica product Rui Costa, he has impressed the Old Trafford club's Portuguese scouts
In addition, Benfica Under-19s captain Joao Filipe previously spent a period on trial at United and is believed to be open to a move to Old Trafford one day
However, the 18-year-old's immediate future appears to be in Lisbon having recently signed a deal until 2022.
Source : PA
Source: PA