The Warriors jump above the Warrington Wolves into second place after the derby win.
And centre Anthony Gelling was the hero for the home team as he bagged a hat-trick.
The Warriors were quick out of the traps, Gelling showing great strength to somehow ground the ball in the corner despite the challenge of several Saints’ players.
Matty Smith nailed the conversion to give Wigan a 6-0 lead.
Dan Sarginson thought he had extended Wigan’s lead but the try was ruled out after George Williams’ forward pass.
Gelling went across for a second time in the half after being put in by John Bateman.
A Matty Smith drop goal just before the hour mark further increased Wigan’s lead over their opponents.
Gelling secured his hat-trick and most likely victory for the Warriors in the 65th minute, intercepting Jordan Turner’s pass eighty yards out before running the length-of-the-field and diving over.
A late dash over the line from George Williams added insult to injury after Taulima Taitai’s carry.