Sheffield United lost for the third time in five games this season as their poor start to the League One campaign continued.
Antony Kay - the former Barnsley and Huddersfield Town players - scored the winning goal for the Dons with three minutes remaining.
United, who are set to welcome fresh investment from Dubai next week, have not won in the League since the opening weekend when they defeated Notts County.
To make matters worse for manager David Weir, Febian Brandy was sent off in stoppage time.
Weir said: “The lack of goals is a concern and it’s disappointing to lose.”
On the news of the investment coming into the club, Weir added: “It’s very positive for club. We hope for benefit on and off the field.
“It puts us in a better position than we have been.”