Wigan took a nervous step towards Premier League survival at the expense of old boss Paul Jewell, still without a win since taking the Derby job and now contemplating life in the Championship next season.
Steve Bruce had demanded goals from his strikers, but it was Austrian defender Paul Scharner who set Latics on their way claiming his fourth of the season in the second half.
And Wigan made sure six minutes from time when Wilson Palacios picked out Antonio Valencia and the Ecuador international smashed in an unstoppable left-foot shot to register his first league goal of the season.
Keeper Roy Carroll had marked his Wigan return by denying the Latics an early lead with a quality reflex save.Mario Melchiot swung in a terrific ball from the right, but Kevin Kilbane's diving header was not good enough to beat the ex-Manchester United and Rangers keeper.
Man of the match Kilbane, freed from defensive duties at left-back with Swede Erik Edman getting his debut, was prominent throughoutand hammered an early shot over the bar.
Like Scharner, he also failed to beat the Derby wall with a well positioned free-kick.
Wigan were out of luck when a Melchiot back-heel was cleared by Giles Barnes although the replay suggested the ball might just have been over the line.
The Rams were largely on the back foot but still had a couple of chances with Stephen Pearson shooting straight at Chris Kirkland and Kenny Miller firing over after chasing a long clearance into the Wigan area.
The Latics had a great chance just before the break when Michael Brown intercepted a sloppy pass by Robbie Savage and headed into the Derby area.
He aimed the cross to the feet of Emile Heskey but the big striker failed to capitalise on the opportunity and there was no problem for Carroll.
But the England star played a big part as Wigan finally broke the deadlock after an hour.
Kilbane's corner was headed on by Melchiot and Heskey had two stabs at it and, although Carroll managed to push the ball clear, Scharner was lurking inside the six-yard area to give the Latics the advantage with a precious goal.
Keeper Kirkland protected the lead saving from sub Emanuel Villa, who tested him with an overhead shot and Melchiot was inches away with a header before Valencia doubled the advantage to wrap up three crucial points.