The 22-year-old, signed for £7million before the World Cup, came off the bench to score in the last minute of this topsy-turvy tie against Wolves and secure a 3-2 win.
Hernandez scored both goals for United against Stoke on Sunday and is fast becoming a new hero to a club traumatised by the Wayne Rooney saga.
Ferguson said: "He was absolutely brilliant - it was a magnificent goal. He's shaped to shoot, dummied the defender and finished really well.
"They tend to build heroes quickly here but he's justifying the praise at the moment.
"He's very professional, the first out on the training ground and the last one back in every day and he's rightly getting a lot of praise for his goalscoring.
"When he gets a chance you know he's going to take it. His touch, control of the ball and vision are improving and that's because the training is intense - we care about it and making sure the players do improve."
Ferguson said the fact that Hernandez speaks excellent English has been "essential" for him settling in so quickly and suggested that is why Bebe may not have been so quick to do so.
Bebe, the relatively-unknown striker signed in the summer for £7.4million from Portuguese side Vitoria de Guimaraes, crowned a promising first start with the opening goal that owed much to fortune - and to assistant referee Darren Cann spotting it had crossed the line - before George Elokobi equalised.
Park Ji-sung made it 2-1 to the home side but Kevin Foley hauled Wolves level again until Hernandez's excellent finish.
Wolves manager Mick McCarthy was delighted about his side's performance but distraught about the result - and he picked out 24-year-old winger Matt Jarvis for particular praise and tipped him as a future England prospect.
"He was terrific, he's a very important player for us," said McCarthy. "I sat next to Fabio Capello's assistant Franco Baldini at Stoke on Sunday and he spoke highly of him.
"We responded very well to their goals and came back twice and if we keep playing like that then I believe it will turn for us."