Cannon grabbed his first goal in a blue shirt as he sent his side on their way to a 3-1 win at Fratton Park.
The victory lifted Kenny Jackett’s men back into the play-offs and it’s a five-point gap to the top of the table.
MK Dons made it hard, however, arriving off the back of five unbeaten games and showcased a passing game which troubled Pompey at times.
Cannon felt his team worked out what was needed to deliver success and then executed the victory well.
He said: ‘They were good and they made us work hard for it.
‘They are a good team and a lot better than where they currently sit in the table.
‘They obviously work on playing out a lot, but there are always ways to work around things and we managed to do that.’