Fernandes will be eligible to play in that game at the Estadio do Dragao on Thursday night, with the suspension from his red card in Sunday's defeat to Tottenham Hotspur only applying to domestic games.
Having grown up in Porto, as a fan of their local rivals Boavista, Bruno is more knowledgeable than most when it comes to our next opponent.
United will be looking to respond after the weekend and, although Porto lost their Europa League opener against Norwegian side Bodo/Glimt last week, their recent results in Liga Portugal have been positive. Sunday's 4-0 win over Arouca was their third successive domestic victory since losing to Sporting CP at the end of August.
"It's a side that always does really well in Europe, we have to be aware of that," Fernandes told MUTV.
"It's a team that has a great spirit, [are] improving a lot in the last few games, even if they lost the last game in the Europa League.
"It is a team that has been improving under their new manager," he added, referencing the promotion of Vitor Bruno, who is now the man in charge after spending seven years as an assistant.
"We expect a really difficult game there, but we go there to win because it’s everything that we have to think about."
United haven't faced Porto since 2009, when Cristiano Ronaldo's famous thunderbolt from distance in front of a hostile local crowd secured our aggregate win in a Champions League quarter-final tie.
Our only other trip to the Dragao, which opened in 2003, was a narrow 2-1 defeat to Jose Mourinho's eventual European champions in 2004.