After United drew a blank in the midweek 0-0 Champions League [ Images ] draw with Olympique Marseille [ Images ], manager Alex Ferguson [ Images ] restored Mexican international Hernandez to the line-up alongside Wayne Rooney [ Images ], with Dimitar Berbatov [ Images ] relegated to the bench.
On a day when the five sides below United were not playing, including second-placed Arsenal [ Images ], who face Birmingham City [ Images ] in the League Cup final on Sunday, Hernandez justified his selection with his eighth and nine league goals of the season.
"To win 4-0 away from home at a place like Wigan is very good, especially as it's a new pitch (at the DW Stadium) and Wigan were committed, particularly early on," Ferguson told Sky Sports.
"We have a big week ahead and it's a good start," added the Scot, whose side play away at fifth-placed Chelsea [ Images ] on Tuesday and then travel to Anfield to play bitter rivals Liverpool next Sunday.
Hernandez touched in Nani's cross at the near post to give United the lead on 17 minutes and he slotted in his second 16 minutes from time after linking up with Rooney.
The England [ Images ] striker then tapped in a third on 84 from substitute Berbatov's pass and defender Fabio Da Silva got the fourth.
Wolverhampton Wanderers moved off the foot of the table and out of the bottom three by thrashing 10-man Blackpool 4-0 at Molineux.
Sylvan Ebanks-Blake scored twice for Wolves, who made their extra man count after Blackpool's leading scorer DJ Campbell sent off just before halftime.
In other games, Jermaine Beckford scored twice to give Everton a much-needed 2-0 win at home to Sunderland and Ashley Young [ Images ] also netted two as Aston Villa [ Images ] won 4-1 at home to Blackburn Rovers, who had defender Ryan Nelsen sent off. Newcastle United and Bolton drew 1-1.