Wigan bounced back quickly from their shock defeat by now-relegated Wimbledon as they condemned Gillingham to a tenth home defeat of the season.
The match was postponed from a month ago due to icy weather but it was the Gills who froze this time with one of their most disappointing displays of the season.
Boss Andy Hessenthaler put great faith in his team having four home games to boost their chances of climbing the table.
Now they face a tricky trip to West Brom on Saturday followed by a real six-pointer against fellow strugglers Walsall on Easter Monday.
Wigan started brightly, and once Nathan Ellington and Jason Roberts had put them 2-0 up they were always in command.
Ellington had already had one effort disallowed for offside before he touched in the opener just past the half-hour.
Jimmy Bullard's free-kick picked out Ellington at the far post as he pounced to score his 17th of the season.
Roberts was the constant target of the home fans, but he silenced his critics as he doubled Wigan's lead three minutes before the break.
He turned sweetly around Chris Hope to net his fourth in four games since returning from a three-game suspension.
Ellington might have grabbed a second but having jinked his way into the box wanted one touch too many and Steve Banks pulled off a fine save.
Gillingham started in a 4-3-3 formation but their first real effort fell to midfielder Alan Pouton who tested Wigan keeper John Filan with a low 20-yard drive that the keeper parried away for a corner.
Roberts was booked for dissent after taking his arguments with assistant referee Ian Bentley too far and Leighton Baines was another yellow card recipient for bringing down substitute Matty Jarvis.
Alan Mahon headed the third goal midway through the second half.
Gillingham coach Wayne Jones admitted: "It's not chins on the chest time just yet and we won't be hoisting the white flag.
"The manager tore into the players both at half-time and again at the end because quite frankly our performance was not good enough." Wigan boss Paul Jewell said: " We looked like our old selves tonight. I threatened changes but if I was a player I would want another chance to prove myself and they responded well." This was a repeat of the second division play-off final in May 2000.
Gillingham won on that occasion to signal their arrival in division one for the first time.
Now it could be that both teams head in the opposite direction come the end of the season.