It was the club's lowest point of the season, their fourth defeat in seven Premier League games.
Old Trafford's atmosphere was called "toxic", the performance was "embarrassing", and United's team was "the worst in 30 years" after that result on January 22.
But with just one signing later, United seemed transformed. They are the team in the best shape in the last eight games since the arrival of Fernandez and doom and gloom have risen completely.
A lively, free-flowing style emerges under Ole Gunnar Solskjaer - with the heart of Fernandez.
Against Brighton, the 25-year-old midfielder - dubbed "Portuguese splendor" by supporters - scored twice in a 3-0 victory, including a brilliant volley to keep his team in charge of the Champions League qualifiers.
The former Sporting Lisbon man was full of life in his 64 minutes on the field, connecting well with Paul Pogba, but also showed his defensive abilities in three games, winning the ball twice.
"Fernandez could only play for 10 minutes and I would rate him as the man of the match," former England international Karen Carney told BBC Radio 5 Live. "He is just so elegant and it was a privilege to watch him play. The difference he made for this Manchester United team is incredible.
"I think Manchester United needs another attacking midfielder, but this midfielder is exciting. Fernandez is fantastic and I was surprised he came out."
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In the 12 games in which he competed in all competitions, United won eight and ended in a draw in four games, scoring 28 goals and conceding just four.
Since his debut in February, Fernandez has been directly involved in more goals in all competitions than any other Premier League player, with six goals and four assists.
United are two points behind fourth-placed Chelsea and three behind third-placed Leicester, whom they face on the final day of the campaign in a match that could still be a shootout for a place in the Champions League.
The victory in Brighton climbed United to fifth place, which would already be enough for a place in the Champions League, if the ban of Manchester City from European competition is observed.
"We are fighting for a place in the Champions League and we know we can achieve that," Fernandez said.
As early as January after the loss of Burnley, Solskjaer was under increasing pressure and said that after this game his country "is not good enough" and "there are no ideas".
His words were quite different after their dominant victory in Brighton.
"They have reason to be confident because they play fantastically," Solskjaer told BBC Sport. "There is quality in this team, our players are fit and now we have competition for places.
"I have more than one player who can reverse the development of the match, we have several top players. Bruno came and was fantastic. He brought this winning mentality with him."
"It's a joy to watch them when you see them rejoicing."
Category: Football analyses
Tags: Premier League, Manchester United