It's set up for a cracking Play-Off second leg at The Den on Tuesday night after The Lions fought out a 0-0 draw in the first leg at Huddersfield, but had no luck as referee Darren Deadman decided in the home side's favour on a couple of key occasions.
Millwall put in a hard-working controlled display at the Galpharm, restricting high-scoring Huddersfield to just a handful of clear cut chances, and had two excellent penalty appeals of their own turned down.
The Terriers started brightly and after just three minutes Gary Roberts saw his fine cross from the left clawed away by David Forde.
The Lions then repelled two early Huddersfield corners before launching their first meaningful attack on the 10 minute mark that might easily have led to a goal.
The ball was worked across to Scott Barron whose shot was blocked two handed by Peter Clarke but Millwall's vociferous penalty appeals were waived away by referee Deadman.
Steve Morison suffered a cut head after a clash with Neal Trotman, but soldiered on with a head bandage.
There was a let off for Millwall on 26 minutes when Lee Novak crossed from the right forcing Darren Ward to make a great challenge on Jordan Rhodes who shot over.
The first yellow card of the game was shown to Paul Robinson who fouled Rhodes on the edge of the box. Drinkwater's curling free-kick was well saved by Forde at the expense of a corner.
Millwall enjoyed a spell of pressure towards end of the half with a series of free-kicks and corners but were unable to carve out a chance.
On 52 minutes a lightning Millwall break ended when Harris cut inside and tested Alex Smithies from 20 yards.
Gary Roberts was fortunate that the referee failed to spot a stamp on Jimmy Abdou, and Mr Deadman's eyesight was again called into question as Millwall had a second blatant penalty turned down when Barron was tripped in the box by Peter Clarke as he was about to pull the trigger.
Harris was then booked for flicking the ball home with a hand from a Barron corner.
Huddersfield also had ball in the net but the flag had long been raised for offside.
Gary Alexander replaced Harris up front, and The Lions only had to survive a couple of scares late on when Roberts fired a deflected shot at Forde and then on 84 minutes Peltier hit a swinging cross, but Rhodes and Novak couldn't get a vital touch.
So all to play for on Tuesday night, but the task might have been a little easier had the referee upheld those penalty claims.

Huddersfield Town: Smithies, T.Clarke (Williams 89mins), Trotman, P.Clarke, Peltier, Roberts, Kay, Drinkwater (Collins 89mins), Pilkington, Rhodes, Novak. Subs not used: Eastwood, Robinson, Simpson, N.Clarke, Eccleston,

Millwall: Forde, Smith, Craig, Abdou, Robinson, Ward, Barron, Laird, Trotter, Morison, Harris (Alexander 70mins). Subs not used: Sullivan, Frampton, Obika, Grabban, Fuseini, Price.
Bookings: Robinson, Harris, Alexander

Ref: D. Deadman
Attendance: 14,654 (Away 1,860)