Poul Hubertz kept Millwall's play-off hopes alive when his late strike earned the Lions a share of the spoils. Michael Higdon headed home Rodney Jack's cross to put Crewe ahead but Millwall equalised when Darren Byfield nodded in a Neil Harris cross.
Crewe looked to have snatched victory in the 83rd minute when Darren Moss turned in a Ryan Lowe corner.
But Millwall were not to be outdone and substitute Hubertz struck from 12 yards to level things up.
Millwall: Pidgeley, Senda (Hubertz 79), Robinson, Shaw, Craig, Dunne, Elliott, Brammer, Brighton (Hackett 69), Harris, Byfield.
Subs Not Used: Day, Ardley, Zebroski.
Goals: Byfield 44, Hubertz 90.
Crewe: Williams, Woodards (Bignot 74), Baudet, O'Donnell, Moss, Lowe, Cox, Jones, Roberts, Higdon, Jack (Matthews 86).
Subs Not Used: fon Williams, Pope, Carrington.
Goals: Higdon 30, Moss 84.
Att: 8,867.
Ref: G Sutton (Lincolnshire).