A superb second-half strike from Chile international Jean Beausejour was enough to give Wigan a 1-0 victory which takes them to three points off the top six
Derby failed to score for the first time since Steve McClaren became head coach at the end of September.
Wigan had the best of the first half without taking several good openings but all that changed in the 68th minute when Beausejour exchanged passes with substitute Callum McManaman before sending a left-footed shot past Lee Grant from the edge of the box.
Derby created little until the last 15 minutes when first Simon Dawkins took an extra touch in front of a gaping goal before having a shot deflected wide and then top scorer Chris Martin failed to turn in an Andre Wisdom cross in the 85th minute.
But Wigan were good value for a victory that avenges the 3-1 home defeat to Derby in December and Rosler revealed: "We had a gameplan and played differently than they expected us to.
"We decided not to play our passing game and wanted to have a high line and I think it worked very well. We had more attempts on goal and the better chances in the first half.
"In the second half, the longer the game went we got pushed back and didn't threaten as much which is why I made some changes.
"The substitution played a part in the goal and it was great individual skill from Beausejour. He's a player we can use in all positions on the left-hand side and he showed why he is probably going to the World Cup.
"What I didn't like so much was the last 10 minutes when we allowed them to run with the ball and they had two massive chances.
"Overall, they had more possession but we had more attempts on target and I think we deserved to win the game."
McClaren was philosophical after he tasted defeat for only the second time since he took charge.
"We were done by a sucker punch and Wigan came to stop us playing and frustrate us," he said.
"It was going to be one of those games and I said at half-time it would be won or lost on a set play. Wigan will say they did a great job on Derby and we have to make sure we pay greater attention to details.
"But at the end of the day, we've had good fortune over the recent months and won games when maybe we could have drawn or lost so I've got no complaints.
"We didn't do enough to win this game, although I didn't think we deserved to lose it and it's a harsh lesson."
The consolation for McClaren is that Manchester United have extended the loan on defender Michael Keane until the end of January and he is also hoping to sign Dawkins on a permanent deal from Spurs this month.