The visitors lead at the break through former Dons striker Clive Platt’s goal before home midfielder Jason Puncheon was sent off for an ugly two-footed lunge on Dean Hammond on the hour.
But five minutes later Wilbraham was left in acres of space to head in Jemal Johnson’s corner and Dons held-on for a point to move six points clear of third place.
The U’s who had won their last three games on the road went ahead after 11 minutes when Platt flicked in Mark Yeates’ cross.
Dave Perkins was denied a second by Willy Gueret and the Dons were up against it when Puncheon, re-signed on-loan earlier in the day from Plymouth, lost the plot with an awful challenge on Hammond.
But the promotion chasers refused to lie down and were level when Wilbraham was left unmarked to head past James Walker.