Wigan took advantage of a dreadful Manchester City performance to secure a first win in seven games.
Dunne headed past his own keeper after four minutes
They went ahead after just 67 seconds when Emile Heskey connected perfectly to fire home an Emmerson Boyce cross.
Less than three minutes later Richard Dunne inexplicably headed into his own net from Josip Skoko's free-kick.
Henri Camara took advantage of hesitancy by City's defence to score and Antonio Valencia added a fine fourth with a right-foot drive.
The win gives Wigan some breathing space at the foot of the table but the way the visitors collapsed will raise some questions for Manchester City boss Stuart Pearce.
His side have now taken just five points from the 15 Premiership games on their travels since they were beaten 4-3 at the JJB Stadium on Boxing Day last year.
City never looked like improving that record once Heskey had put Wigan in front.
The big striker produced one of the only moments of quality in the game when he swung out his right leg to dispatch Boyce's centre past City keeper Nicky Weaver.
It was the 28-year-old's 96th goal on his 350th Premiership appearance.
And worse was to follow for City with just four minutes on the clock.
Skoko swung a free-kick into the box and, with no Wigan players attacking the ball, Weaver came out but failed to collect as Dunne glanced a header into the empty net.
It took 22 minutes for City to even manage an attempt on goal, and even that was an ugly effort well wide by Bernardo Corradi.
City's frustrations were illustrated by bookings for Joey Barton and Dietmar Hamann for a couple of late lunges.
Paul Jewell's side were not at their best but they rarely needed to be as City's defence repeatedly came to their aid.
Paul Scharner seemed to have the freedom of the City box and could have had a hat-trick of headers.
Darius Vassell came off the bench to provide a brief moment of hope when he was played in by teenager Michael Johnson on his City debut, but the striker shot wide.
Two further goals in just over two minutes ensured just a second win of the season for Wigan.
They beautifully carved out their third but were given another helping hand by the City defence.
Leighton Baines started the move and then made an ambitious run into the box where he was picked out by Kevin Kilbane.
Baines' square ball should have been cleared by Stephen Jordan but Camara pounced on his half-hearted clearance to deflect past Weaver.
City's defence was nowhere to be seen moments later as Heskey picked out Valencia to stride into the box and drive into the bottom corner for his first goal in English football and complete City's misery.
It was the biggest victory for Wigan in their brief Premiership history and the heaviest defeat of Pearce's 19-month reign.
Wigan boss Paul Jewell:
"I don't think it was a fantastic performance, it was a sound one. We deserved to win but the score wasn't a true reflection.
"There are a lot of new players here who are settling in and we will get better as the season goes on.
"There is room for improvement all over the pitch, but you can't be unhappy with a four-nil win."
Manchester City manager Stuart Pearce:
"You don't give yourselves a chance when you go 2-0 down after four minutes.
"When you go away from home you hope to keep it tight and quiet the home crowd down, but we did the opposite.
"Man-for-man, we didn't compete well enough and in the second half we lost our shape trying to chase the game."
Wigan: Kirkland, Boyce, Hall (Webster 46), De Zeeuw, Baines, Valencia (Teale 83), Skoko (Landzaat 30), Scharner, Kilbane, Heskey, Camara.
Subs Not Used: Pollitt, McCulloch.
Goals: Heskey 2, Dunne 4 og, Camara 65, Valencia 67.
Man City: Weaver, Mills (Vassell 60), Richards, Dunne, Jordan, Sinclair, Johnson, Hamann (Dickov 46), Barton, Samaras, Corradi.
Subs Not Used: Hart, Onuoha, Laird.
Ref: P Dowd (Staffordshire).