Some abysmal defending by the Terriers allowed Southampton to return home with all three points.
Nathan Redmond and Michael Obafemi found the net either side of Danny Ings converting a penalty on an afternoon when Town were their own worst enemies with a performance that was way, way short of the standard required in the Premier League.
This was particularly the case in a first half that saw a midfield minus the injured Jonathan Hogg being over-run by the south coast club.
Philip Billing did spark a mini-revival for Huddersfield just before the hour but another calamitous mistake - this time by Christopher Schindler - meant David Wagner’s men lost once again.
Town fell behind in the 15th minute. With Hogg absent due to a knee injury, Alex Pritchard was moved back into centre midfield and he was unable to prevent Danny Ings finding Pierre-Emile Hojbjerg.
He, in turn, looked up before threading a delightful through ball for Redmond, who beat Jonas Lossl with a fine finish.
Southampton doubled their lead just before the break. A lazy attempt at a tackle from Mathias ‘Zanka’ Jorgensen brought Danny Ings crashing to the ground and referee Stuart Attwell rightly pointed to the spot.
Ings made no mistake with the penalty, sending Lossl the wrong way.
Billing gave the hosts hope with a wickedly swerving shot from 25 yards that Alex mcCarthy was unable to keep out despite the ball hitting the middle of the net.
Town pushed for an equaliser but McCarthy dealt comfortably with efforts from Alex Pritchard and Isaac Mbenza
Southampton, however, were destined to score the fourth goal of the game. Schindler, in trying to shepherd the ball back, slipped to allow Redmond to claim possession and roll a pass for substitute Obafemi to convert.
Manager David Wagner said: “The frustration today is more about our first-half performance because I think the first half was the worst in a long period that we played.
“It looked like recent results affected us, we looked nervous and in possession we were not calm enough. We rushed situations, we were not brave enough on the ball, we passed too often backwards.
“The reaction in the second half was better. We were able to score, everybody was livening up and we had a lot of further opportunities and then we conceded the third one.”