Fernandes scored from the spot on the night as United were twice pegged back and had Harry Maguire sent off. The visitors also felt they were denied a penalty for a disputed foul on Amad Diallo.
Fernandes said afterwards: "Disappointed because we did enough to get three points. Had to finish with a lot of suffering and trying not to concede. Frustration onto ourselves because we could've gone 2-0 up and from that we conceded another goal.
"Not getting a penalty and then we get a penalty against where it's the same situation as Amad - one is one, one is not. I know it's difficult for the referee to give two penalties to the same team in one game but I don't understand why VAR doesn't get involved in that situation or with Harry (Maguire) because either one is a penalty and so is the other or none of them are.
"Amad is getting to a point where he's going to shoot and he gets pushed - you can see that something puts him completely out of balance. It's frustrating for the small players because they always say the small players are soft and when it's the bigger players they end up giving the fouls. I think the other situation is a penalty but I also think the one on Amad is a penalty and that could've changed the game."
On United's players now being praised instead of criticised, Fernandes added: "It will always be like that when you get results you get flowers when you don't you get criticised it's part of being a Manchester United player.
"Demand is very high from everywhere, a lot of people with eyes on the club because it's massive. It's a lot of eyes on us but if you decide to play for this club and you play here then you are a big player and have a big personality. There are highs and lows and you have to deal with them. "