Wilbraham made up for an earlier miss by poking the ball home from close range as MK Dons sank fierce rivals Northampton 1-0.
Dean Lewington had earlier crossed an inviting ball in the box and found Wilbraham, who beat Chris Doig to the ball but somehow failed find the net with his header.
The Cobblers grew in confidence as the game wore on and should have taken the lead when Adebayo Akinfenwa was clean through on goal only to fluff his left-footed shot.
But the deadlock was finally broken in the 66th minute in controversial fashion.
Wilbraham scrambled in Peter Leven’s corner at the back post despite the efforts of Danny Jackman, who claimed to have cleared the ball off the line.