Millwall were left ruing a string of missed chances as Port Vale completed a smash and grab raid courtesy of Akpo Sodje's 70th-minute leveller.
The Lions had looked to be on their way to three thoroughly deserved points courtesy of Chris Zebroski's 20th-minute strike.
But having dominated proceedings and created a stackful of opportunities, Vale made Millwall pay by snatching an equaliser against the run of play.
It was a bitter pill for Willie Donachie's young charges to swallow, having worked so hard to not only establish an advantage, but then carved out enough chances to kill off the game.
Martin Foyle's Vale outfit had been involved in an energy-sapping Carling Cup clash with Norwich City in midweek, and that certainly showed in a lacklustre display from the visitors.
It was all Millwall from the off, and Marvin Williams effort was somehow kicked off the line by keeper Mark Goodlad on nine minutes.
Even though The Lions had to re-shuffle a minute later when Mo Ross hobbled off to be replaced by Danny Senda, Donachie's side swiftly adapted and continued to press for the opening goal.
Williams and Chris Hackett both delivered teasing crosses that needed just a touch in front of goal, while Poul Hubertz was proving a handful for the visiting defence.
Millwall finally got the goal their pressure deserved on 20 minutes when Tony Craig did well to find Hubertz, he in turn flicked the ball on to Zebroski who hit a rasping angled drive beyond Goodlad's reach.
Senda nearly added a second with a curling free-kick that the keeper held, while Hubertz's speculative overhead effort flashed wide and another Senda drive was dealt with by Goodlad.
Former Lions striker Leon Constantine should have levelled seconds after the break when, with the goal at his mercy, he contrived to head over from six yards.
That scare sparked an immediate response with Senda's fierce low cross fizzing infront of a cluster of players and Hubertz denied by a superb last-ditch tackle from Jason Talbot as he prepared to pull the trigger.
Hackett was left cursing his luck when a sublime 60th-minute drive slid a foot past the post, as did Zebroski's effort six minutes later.
There only looked to be one team likely to score, but then to Millwall's dismay, Vale snatched an equaliser out of nothing, although there looked to be a hint of off-side when Sodje picked up the ball and thumped home on 70 minutes.
Instead of losing heart, The Lions re-grouped and produced a final period of pressure.
Derek McInnes set up Hubertz, whose effort was blocked, Darren Byfield shot wide when perhaps a slipped pass to the unmarked Hackett would have been the better option and then the ball was somehow cleared following an almighty goalmouth scramble in the last minute.
With that went The Lions last chance of securing three points that would have lifted them out of the drop zone, but with consistent displays of this standard, surely that is now only a matter of time.

Millwall: Pidgeley, Ross (Senda, 10mins), Craig, Elliott, Phillips, Shaw, Hackett, Mawene (McInnes, 75mins), Williams (Byfield, 60mins), Hubertz, Zebroski. Subs not used: Day, Morais.
Bookings: Hubertz (61mins), Elliott (77mins)
Scorer: Zebroski (19mins)

Port Vale: Goodlad, Pilkington, Talbot, Sonner, Walker, Harsley (Husbands, 62mins (Miles, 90mins)), Constantine, Smith (Cardle, 70mins), Whitaker, Abbey, Sodje. Subs not used: Anyon, Walsh.
Bookings: Sonner (10mins), Harsley (26mins)
Scorer: Sodje (71mins)

Ref: Keith Hill
Att: 10,189 (Away 311)