The teams went into the break goalless before Paul Dickov saw his side humbled by a fine second 45 minutes from Posh as goals from Tommy Rowe, David Ball and Gabriel Zakuani were added to by a late brace from top-scorer Craig Mackail-Smith.
Ferguson said: "I am delighted because this is a really top-drawer performance. We got control of the game in the second half and played to our system a lot better by keeping the ball.
"We got some lovely set pieces in to the box which caused problems and it was a really pleasing day because Oldham is a difficult place to come.
"There is no doubt this result sets us up but our away form is going to be very important because when you look at the state of our pitch we are going to enjoy playing elsewhere.
"It's a great win for us and we will look to really kick on from here."
Source: PA
Source: PA