Brentford lost ground in the League One automatic promotion race as MK Dons kept alive their play-off hopes.
The Dons led when goalkeeper Simon Moore allowed Dean Bowditch's 30-yard strike to slip past him.
Brentford created numerous chances, with Marcello Trotta wasting two clear opportunities and Bradley Wright-Phillips heading over from close range.
But MK absorbed late pressure from the Bees and struck a second when Stephen Gleeson rifled in from 20 yards.
Brentford, who came into the game on a three-game winning run, were bright throughout but their lack of cutting edge in front of goal saw them drop three points behind second-placed Bournemouth, although the London side have two games in hand.
The Dons have now won three out of their last four but need to make up eight points if they are to reach the play-offs.
VIEW FROM THE DRESSING ROOM
MK Dons manager Karl Robinson told BBC Three Counties Radio:
"Seven players couldn't start today, that was as difficult as it gets.
"People don't know what we've gone through this year, people don't know how difficult it's been internally, and the injuries we've had and the suspensions we've had.
"It just meant so much to us all, I think you can see by the way we celebrated that goal it meant a lot to us as individuals.
"We will keep going until the end, it's not in my make-up to quit."