Steve McClaren's Rams were sitting pretty at the top of the form table before Jea Beausejour's second half wonder strike at the I-Pro Stadium.
The significance of the result was not lost on Rosler who was full of praise for his sides first game of 2014. Speaking to the club's official website he said: “Today was the perfect start to that and a great performance given by my players against a Derby team who are on a strong undefeated run and second in the league.
“In the first half we had more chances than they did. It was a fairly even game but our game-plan worked; we didn’t invite the pressure onto us they were looking to direct, we went a little more direct, held it up well and caused problems in a number of areas.
“Jean’s goal was superb and he again showed how good a player he is; capable of playing in a number of positions, a real professional and someone with immense individual skill. It’s so easy to see why he will go to the World Cup in the summer.
“Towards the end Derby went route one, bringing on Conor Sammon to apply the pressure aerially. The one aspect that maybe didn’t work too well was that our wing-backs didn’t get close enough to their wide men, which allowed them to cross the ball and made us defend for our lives at times.
“But the supporters helped the players, and I was delighted for them to come all this way and see their year start in this way."
The Latics face a return to action on Saturday against MK Dons at the DW Stadium as they start the defence of the FA Cup title won at Wembley in May.