Two goals in two minutes from Marcus Tudgay and Lee Holmes shortly after the interval helped to ease Derby's relegation fears and left Wimbledon rooted to the foot of the First Division.
George Burley's side began the day just five points above the Dons and it was the visitors who shaded the first half, which ended level despite Nico Herzig's own goal given Derby an early advantage.
Herzig headed the ball past keeper Steve Banks after Portuguese winger Candido Costa had crossed, but Wimbledon responded well and were level within seven minutes, skipper Nigel Reo-Coker beating Lee Grant with a low shot.
However, Derby took the game by the scruff of the neck after the break, taking the lead through Tudgay's smart volley on 52 minutes.
The Rams then doubled their advantage inside 60 seconds as Costa picked out teenager Holmes, whose mis-hit shot found the back of the net.
Holmes, Peter Kennedy and Tudgay then all went close for the home side as they looked likely to extend their margin of victory in a strong finish.
Derby v Wimbledon
