The 23-year-old enjoyed a successful first season at Old Trafford, hitting 20 goals across all competitions following his move from Guadalajara in July 2010.
However, the Mexico striker has struggled to reach those heights so far this campaign, firstly suffering a number of injuries and now going five games without a goal - his longest run without netting since moving to the Red Devils.
The forward is fully fit again but appears to be behind Danny Welbeck in the pecking order and was an unused substitute against Manchester City last weekend.
Hernandez though is refusing to get downhearted, telling the club's official website: "There are different circumstances because I have had more injuries this season than last year, but I am still enjoying it.
"Each year it is going to be more difficult.
"In the first season, not only the defenders but also the coaches didn't know me.
"Now, and in the third and fourth seasons, they are going to know me even more.
"But good players like Wayne [Rooney], [Robin] van Persie and [Didier] Drogba have been here five, six years or more and still play at the same high level.
"I need to keep working to do the same."