Dean Larkin scored the only goal of the game as Bonagee United got the better of Letterkenny Rovers in the Ulster Senior League on Wednesday night.
The result puts a real dent in Rovers' title ambitions.
They remain in third spot in the table, six points off the top. However, Derry City Reserves' win against Swilly Rovers on Wednesday night means they are now just a point behind leaders Cockhill Celtic.
Derry beat Swilly 3-1.
There are three more games fixed for Sunday.