Goals by David Rowson and Joshua Low ensured that Northampton ended the year on a high, stretching their unbeaten run to six matches.
But Bury will be glad to see the back of 2004 as this defeat means they have now gone five games since their last victory, while the sending-off of midfielder David Flitcroft was the sixth red card they had picked up this season.
Rowson's opening goal four minutes before the break was a particular landmark for the Cobblers as it was the former Partick Thistle player's first goal for the club since moving south in the summer.
Rowson curled an exquisite right-foot free-kick into the top corner to set Colin Calderwood's men on the way to a third straight victory.
Those closing moments of the first half proved to be telling as Flitcroft was dismissed in first half stoppage time for the second of two yellow card offences on goalscorer Rowson.
Earlier, Bury had the best chance of the half when Jon Newby crossed from the left to find his strike partner Dave Nugent, but Bury's top scorer crashed his shot against the crossbar.
Northampton could have gone ahead in the 34th minute when Eric Sabin was sent clear by a great pass from Martin Smith, but the striker was unable to hit the target.
Bury countered with Dwayne Mattis, Newby and Brian Barry-Murphy combining, but the latter side-footed wide from six yards when it appeared easier to score.
With their player handicap Bury only briefly threatened to equalise after the break, although Nugent squandered a great chance in the 55th minute seconds after Rowson had seen a dipping drive narrowly clear the bar at the other end.
Bury's current poor run had started with their FA exit here 24 days earlier and their misery was completed 17 minutes from time when a precision pass from Smith picked up Low and the winger poked the ball past the on-rushing Andy Marriott for his fourth goal of the season.