The striker took advantage of defensive hesitancy after 48 minutes to smash the ball into the roof of the net after the Seagulls failed to clear a corner from Jemal Johnson.
Brighton started well but were put on the back foot after defender Adam El-Abd received a straight red card for a studs-up challenge on Richie Partridge in the 26th minute.
French goalkeeper Willy Gueret came to the Dons rescue in only the fourth minute by parrying a goal-bound header from Andrew Crofts following a long throw from James Tunnicliffe. Brighton threatened again when El-Abd exchanged passes with Elliott Bennett before having his low shot saved by Gueret.
Striker Aaron Wilbraham shot straight at keeper Michel Kuipers as Dons failed to make the most of their best opportunity of the first half.
Brighton came closest to equalising when Liam Dickinson's 20-yard shot was parried by Gueret.