The 21-year-old's future is currently the subject of much speculation, with Liverpool and Real Madrid both believed to be keen on a deal for the central midfielder.
Fernandez made the move to Benfica from River Plate in July 2022, and he has represented the Portuguese giants on 24 occasions, scoring three goals and registering five assists.
The midfielder also played an important role in Argentina winning the World Cup, making seven appearances at the competition, scoring once and providing one assist.
Fernandez did not start against either Saudi Arabia or Mexico, but he was then in the XI for the team's next five matches against Poland, Australia, Netherlands, Croatia and France.
According to UOL Esporte, Man United are currently in discussions with the South American over a move to Old Trafford, with the Red Devils determine to win the hunt for his signature.
The report claims that Erik ten Hag's side have moved past Liverpool in the race, with the Reds currently focusing on Borussia Dortmund's Jude Bellingham.
Fernandez has a contract with his current side until June 2027, and there have been suggestions that Benfica value him close to £100m due to his huge impact since arriving over the summer.
Journalist Bruno Andrade claims that Man United would be prepared to pay the midfielder's full £106m release clause in order to secure his signature.
Man United are currently prioritising signing a new centre-forward, as Cristiano Ronaldo's recent departure has left the the team short of options in the final third of the field.
However, a new central midfielder is also believed to be on the agenda despite bringing both Casemiro and Christian Eriksen to the club last summer.
Man United are currently well-stocked in the middle of midfield, but Fred could potentially be on his way out of the club next summer, while Donny van de Beek might also be moved on.
Ronaldo's departure has also saved the club in the region of £500,000 a week in wages, so the club will be in a position to make more high-profile additions next year.
Ten Hag's side will be back in Premier League action against Nottingham Forest on December 27.