Luton went down to Barnsley, while Swindon failed to beat MK Dons.
Barry Fry may have announced his decision to step down as manager at the end of the season but Peterborough's miserable form continues with a 3-0 defeat to Colchester at London Road.
The Posh look destined for the drop and after Colchester's on loan wide man Marc Goodfellow netted on 45 minutes, there would be no way back for the home side.
In-form midfielder Neil Danns doubled The U's advantage with 20 minutes remaining and new boy Marino Keith added gloss to a polished performance when netting a late penalty.
Hartlepool's promotion charge suffered a jolt, as they were beaten 1-0 by Huddersfield - with Andy Booth's header just before the break proving decisive.
Swindon will rue missing a last minute penalty as they could only draw 1-1 at in-form MK Dons, who are now unbeaten in 11 at home.
Andy King's promotion chasers had to come from behind after MK Dons took the lead through Wade Small's strike in the 14th minute.
Midfielder Grant Smith found a leveller just before half time but King was left fuming after the same player failed to dispatch from the penalty spot.
League leaders Luton were off-form at Kenilworth Road as they went down to a 3-1 defeat to Barnsley.
A Chris Shuker double and a Michael Chopra strike gave Barnsley a three-goal lead at half time, while Enoch Showunmi netted a consolation.
Click below for individual match summaries:
Hartlepool 0 v 1 Huddersfield
Luton 1-3 Barnsley
MK Dons 1-1 Swindon
Peterborough 0-3 Colchester
