It was Jonathan Hogg, running in front of the near post and flicking the ball into the net after 82 minutes who decided this game, scoring its only goal.
Had Huddersfield not won it having played so well, it would have been unfair. But then life sometimes is.
They played with patience and no little skill throughout against unambitious but digged opponents who almost got what they came for.
The Terrier were at their best in the opening 45 minutes, with Millwall content to sit off and challenge the Terriers to break them down. As the half went on they began to realise that the most profitable gaps were to be found between the Lions' back three and their midfield, especially when Lewis O'Brien got forward in the inside-left channel.
It made the midfielder the most eye-catching performer, firing a couple of shots wide from distance.
Duane Holmes dropped deep in the 16th minute and played a wonderful pass to Sorba Thomas who crossed the bouncing ball well but just behind Danny Ward, who was unable to control his volleyed finish.
In a tactic his side would use more and more, Danel Sinani drifted into no man's land and produced a nice touch to Thomas. He helped it on to Holmes, who came up against a dark blue wall.
Luxembourger Sinani hit a daisy-cutter from distance and Ward followed up a good turn with a much firmer shot Bartosz Bialkowski was forced to bat away.
O'Brien was brought down by George Saville, who was booked, when he received the ball in the pocket but Holmes hit the free-kick wide.
When Sinani produced a nice pass to O'Brien he cushioned a volleyed cross and Shaun Hutchinson did well to get back and stop Ward converting it.
With little for Lee Nicholls to do - he caused his own problems with one miskicked as Millwall repeatedly encouraged him to go long, it felt like the opening goal was there for the taking if only the Terriers had the patience to allow it to happen.
That was tested more in the second half as Maikel Kieftenbeld was brought on to plug the gaps and Millwall threatend a bit more, Matty Pearson forced to make an excellent tackle on Tom Bradshaw, and Thomas to hack away the resulting corner.
Pearson might have scored by then, Bialkowski saving at a corner, or more likely have had a penalty given that he had shrugged off a very obvious pull of his short to have the chance.
Thomas had a wild shot after a good driving run by O'Brien, and another when he came inside off a pass from susbstitute Josh Koroma, sent on to break the deadlock,.
More changes followed, the Terriers going from 3-4-2-1 to 4-2-3-1 and giving us the rare sight of two of their centre-forwards on the pitch together.
Forget tactics, though, set pieces have been Huddersfield's salvation so often this season and when Ward's excellent volley was saved and Harry Toffolo's follow-up header was scrambled behind, Hogg was able to come to the rescue.
Three bookings for home players after that added to the sense that they were being made to fight for all three points in the way you brace yourself for when Millwall are in town. Toffolo threw himself in the way of a stoppage-time shot by Ryan Leonard.
The reception the Huddersfield players got at the final whistle said it all. This was a big win and despite how well they played, a bit of a relief.
Huddersfield Town: Nicholls; Pearson, Lees, Colwill (Turton 78); Thomas, Hogg, O'Brien, Toffolo; Sinani (Koroma 74), Holmes (Campbell 78); Ward.
Unused substitutes: Aarons, High, Sarr, Bilokapic.
Millwall: Bialkowski; Ballard (Smith 83), Hutchinson, Cooper; Leonard, Mitchell, Saville, Malone; J Wallace, Ojo (Kieftenbeld 46); Bradshaw (Afobe 72).
Unused substitutes: Long, M Wallace, Pearce, Bennett.
Referee: G Eltringham (Tyne and Wear).