The goal was scored against Barnet on the opening day of the 1995–96 season and the conceding goalkeeper was Maik Taylor, who was making his league début.
He started the season as second choice goalkeeper behind Ryan Esson, but was handed his club début on 22 August 2006 in the League Cup match at Birmingham City, which Town lost 1–0.
In the closing month of the season Shearer was being picked ahead of Mackenzie but (due to an agreement made prior to his loan signing) was not allowed to play against his parent-club Bristol Rovers in the League Two play-off final.
On 21 September 2007, Mackenzie joined Conference side Kidderminster Harriers on a month-long loan to provide cover for the injured Scott Bevan.
Mackenzie retired from football on 29 February 2012, during a team meeting which followed Corby Town's 3–1 home win against Long Buckby in the Hillier Senior Cup Semi-final, in which all the players were asked to take a pay-cut.