With Wayne Rooney ruled out through injury and Danny Welbeck consigned to his sick bed, Hernandez was handed striking responsibilities for the Boxing Day encounter with Newcastle at Old Trafford.
The Mexican failed to convert two clear chances to give Man Utd victory, but his luck changed in the final minute when he beat the Newcastle offside trap to reach Michael Carrick's cross and seal a dramatic 4-3 win with his 10th goal of the season.
Javier Hernandez: "I didn't have those things in my mind.
"You cannot afford to regret every chance you miss because if you do you will never be concentrated for the next opportunity.
"You are never going to play the perfect game. You will never score five goals from five opportunities.
"That is the beauty of football.
"The most important thing was the win because here there are no heroes.
"It doesn't matter if I score in the last minute or we score four goals.
We won and Manchester City lost. That is very good news.
"Ask any player in the world and they will tell you they want to play every game, as I do.
"But the competition here is incredible.
"It is the biggest club in the world. You need to be aware there are five strikers who want to be part of the games.
"I have to prove, in one minute or 90, that I want to start."