Goals from Martyn Waghorn, Emmerson Boyce, James McArthur, and Jordi Gomez sealed the victory for the Latics who made it twelve wins in eighteen games for Rosler as manager.
Speaking with pride after the game, Rosler told the club's official website: "It was a huge victory again. We started well and in the first half our left hand side caused them enormous problems.
"We got 1-0 up and probably could have gone further in front, but in general in the first half maybe we looked a bit nervous on the ball. We're not used to having so much time on the ball, but we switched things for the second half and the lads were terrific.
"We scored three goals and it could have been even more, yes we conceded, but it was from our mistake and other than that we didn't let them in."
The result propelled the Latics up to sixth place in the league, three points behind fifth placed Forest and with a game in hand.