After back-to-back Easter wins against Hartlepool and Sheffield Wednesday, Huddersfield made it nine points out of nine in a London Road clash where midfield man Chris Brandon was the difference between the two sides, scoring one goal and setting up the other.
Huddersfield started brightly and Brandon was quick to exploit poor Posh marking to seize a loose ball and give goalkeeper Mark Tyler no chance with a 21st minute shot from just inside the penalty area.
Huddersfield looked set to quickly double their advantage but Tyler, celebrating his 28th birthday, denied the threatening Andy Booth when going full stretch to produce a fine save.
Posh hauled themselves level on the stroke of half time with Wayne Purser getting the vital touch to a cross from the impressive Chris Kanu to claim his sixth goal of the season.
After the break, Purser was close to goal number seven when seeing a fierce shot crash against the crossbar.
Although relegation now looks inevitable, Posh played with spirit and had the better of second-half exchanges with Steve Thomson causing problems from the middle of the park.
Despite being clattered by Adnan Ahmed, who was immediately substituted after getting an inevitable yellow card, Thomson bounced back to bring a fine stop from Phil Senior.
Posh were caught on the break when Brandon again turned on the style making a determined run to feed substitute Danny Schofield who confidently fired Huddersfield's winner with six minutes left.