Fernandes has started 25 of United’s 31 games this season but Donny Van De Beek was preferred to the Portuguese for the visit of Jurgen Klopp’s men at Old Trafford.
Fernandes appeared as a 66th minute substitute and promptly struck the winner from a free kick twelve minutes from time to help United to a 3-2 victory and advance to the fifth round of the FA Cup where they will meet West Ham United.
The 26-year-old former Sporting Lisbon man had gone four games without a goal before his heroics on Sunday, leading to suggestions that he was starting to tire but Fernandes intends to keep going.
"Tired? At 26 years old I can't be tired. If I'm tired now, when I arrive at 30, 32, I will not play. I will play one game in five so, no, I'm not tired," he said after his cameo role in the FA Cup victory.
"Of course the coach knows what is better for the team and today he choose to play with Donny to give some freshness to the team.
"I think it's fair enough because Donny is training really well, he's been important for us and will be more and more important in the future."
Manchester United, who are top of the Premier League, host Sheffield United in midweek before travelling to Arsenal at the weekend.
