Pat Richards's second try, eight minutes from time, clinched a Wigan win which had at one time looked inevitable but which finally had to be earned against a determined St Helens resurgence.
"I thought Pat Richards was far and away our best player," said the Wigan coach, Shaun Wane. "He's been consistently fantastic for us this season."
Richards also kicked four goals for a personal tally of 16 points in a match featuring some spectacular tries and some hugely impressive performances from players new to the demands of this derby.
The young Wigan prop Dom Crosby stood out, with a crucial try and plenty of powerful running, while Blake Green, in his first season at the club, exerted more control over the action than anyone.
For Saints, the giant front-rower, Alex Walmsley and the fleet-footed Mark Percival might have finished on the losing side, but their promise for the future was plain to see.
Injuries meant that Saints fielded a strange-looking side, with Paul Wellens and Jon Wilkin – a full-back and a second-rower – as half-backs and Stuart Howarth, once of Wigan, making his debut at hooker. Sometimes, a makeshift side can pleasantly surprise everyone, including the team themselves; in the first half there was not a hint that this might be one of those occasions.
Wigan were simply too incisive to let opponents settle into unfamiliar roles and soon led through beautifully crafted team tries finished by Richards and Sam Tomkins.
Even when Saints staged a rare attack, it blew up in their faces. They showed great initiative in keeping the ball alive in Wigan's 20, but when it went to ground Josh Charnley scooped it up and run 90 metres to touch down.
Saints were reinvigorated after the break, putting the Warriors under concerted pressure for the first time and getting their reward through Paul Clough.
Crosby replied for a Wigan side itself lacking four regular props, but back-to-back tries from Francis Meli and Tom Makinson gave St Helens the glimpse of the sort of unlikely come-back victory in which they used to specialise. But the outstanding Liam Farrell's lofted pass sent Richards away and a derby which sold out the DW Stadium for a seventh year running was decided.
Wigan: S Tomkins; Charnley, Goulding, Thornley, Richards; Green, Smith; Crosby, McIlorum, Flower, Tuson, Farrell, O'Loughlin. Substitutes used: Hughes, Taylor, L.Tomkins, Burke
St Helens: Makinson; Gardner, Turner, Percival, Meli; Wellens, Wilkin; Laffranchi, Howarth, McCarthy-Scarsbrook, Jones, Manu, Walker. Substitutes used: Flanagan, Clough, Walmsley, Soliola.
Referee: R.Silverwood (Mirfield).