Former Portugal captain Costinha has been impressed with the "fantastic" performances of his compatriot Bruno Fernandes since his arrival at Old Trafford, and feels the midfielder can lead the Red Devils back to the very top of the game.
Fernandes joined United from Sporting C.P. during the January transfer window in a deal worth an initial €55 million (£47m/$60m) and has made an instant impact on Ole Gunnar Solskjaer's side.
The 25-year-old has contributed three goals and four assists in his first nine appearances for the club as United push for a place in the Premier League's top four as well as gunning for trophies in the FA Cup and Europa League.