Wigan coach Shaun Wane opted to play his strongest side available and it paid off as the Super League giants ran in five tries in the opening 18 minutes on their way to a 36-4 half-time lead. Josh Charnley opened the scoring inside two minutes.
Dewsbury responded with a spell of pressure but Wigan counter attacked swiftly and Charnley grabbed his second.
Oliver Gildart dummied through and stepped behind the posts to give Charnley a simple conversion.
Williams then sent full-back Dan Sarginson racing over and Charnley’s conversion gave Wigan a 24-0 lead.
Dewsbury responded superbly and stand off Paul Sykes spotted a gap, which he raced through to dive over for an unconverted try.
Wigan then clicked back into gear as Williams and Smith linked to set up a lovely try for John Bateman.
Bateman beat two Rams defenders to score a second. The Warriors added an eighth try when Ryan Sutton stretched over, before Gildart scored.
Dalton Grant went close for the Rams as he raced down the touchline but was tackled inches short of the line but Lewis Tierney brought up Wigan’s half century when he stretched over and Charnley tagged on his seventh goal.
To Dewsbury’s credit, they dug deep to deny Wigan further points in the final 24 minutes and they were almost rewarded with a second try but Jason Crookes knocked on.
Dewsbury: Guzdek; Kudangirana, Crookes, Grady, Grant; Sykes, Kain; L Adamson, Speakman, Teanby, Hale, Trout, Farrell. Subs: Conroy, Brown, Muranka, Walker.
Wigan: Sarginson; Manfredi, Gelling, Gildart, Charnley; Williams, Smith; Crosby, Powell, Mossop, Bateman, Isa, O’Loughlin. Subs: Tautai, Sutton, Tierney, Burke.
Referee: Chris Campbell.