Three goals in a 16-minute spell late in the second half ensured Northampton chalked up a fifth consecutive home win in Division Three.
Trailing to Kevin Townson's 12th goal of the season, the Cobblers were able to swing the result on the back of the 61st minute sending off of 'Dale skipper Gary Jones.
It hadn't looked like being a good afternoon for captains, as it was a mistake by home skipper Paul Reid which enabled Townson to fire in the 32nd minute opener.
Jones was shown a yellow card by referee Ray Olivier in the 57th minute for retaliating after a late challenge by Chris Hargreaves, which also saw the home player booked.
Four minutes later Jones went in heavily on Martin Smith, and he was given his marching orders.
Northampton drew level in the 69th minute when Hargreaves swivelled sharply to volley in his fourth of the season after good work by Magno Vieira in drilling a low cross back into the box.
And 11 minutes later it was 2-1 when Smith's in-swinging corner was headed in at the near post by Reid for only his second of the campaign.
Northampton hadn't scored three at home in a League match since November 2002, but they were able to end that unwanted sequence five minutes from time when Neil Edwards dropped another Smith corner and Vieira was able to prod the ball home from close range.
Dale boss Steve Parkin was far from happy as his side's dismal away form continues to drag them down but he had no doubts as to where the blame lay.
He said: "Up to the sending off we were well in control. It was a poor decision by the referee for the first booking and once he has done that there is no margin of error.
"He put himself under pressure by showing his forgetfulness by whistling early at the end of the first half which the crowd picked up on and wasn't able to hold his nerve after that." The victory lifts Northampton three more places in the Division Three table and keeps alive their hopes of a late season push for the play offs.