United suffered their second loss of the season last Saturday as they were stunned 3-2 at Old Trafford by Andre Villas-Boas's side.
"Now we need to take back some of the league points that we dropped at Old Trafford. We know it won't be easy but we're working very hard to try and not make the same mistakes we made against Tottenham," Hernandez told the Red Devils' official website.
"It's not going to be easy for us because we know they did really well last season and at their home, their performance [against us] was very, very good."
Hernandez has scored once in seven appearances for United this season.