Norwich City came away from The Den with a vital three points in their play-off push, thanks to a resilient second-half performance.
Level at the break, City would push ahead by two before Millwall threw everything at David Wagner's men in the closing stages.
The atmosphere was tense in the capital with both teams searching for those three vital points in the play-off battle.
The home side would press first and had a couple of long-range throw-ins to try and pressure Angus Gunn.
Their breakthrough arrived after 20 minutes when Tom Bradshaw stole in between Grant Hanley and Ben Gibson, then held his nerve to finish to the roof of the net.
Oliver Burke almost made it two immediately after but pulled his effort across the face of the goal.
The Canaries fashioned a response in the shape of a clever corner-kick routine.
When attention followed the players rushing into the penalty area, Gabriel Sara instead picked out Jacob Sørensen who slotted home from 18 yards.
A better Norwich finished the half with more of the play going into the home side's territory.
And that carried into the second half with Norwich nudging in front inside the opening 10 minutes.
Another set-piece routine, this time a short pass to Onel Hernández allowed the Cuban to step in along the byline.
His pass across goal was diverted into his own net by Bradshaw.
It got better for the Canaries when the winger provided yet again - powering his way down the line before picking out Gabriel Sara who turned and finished sublimely via the crossbar.
The hosts weren't willing to fold however, and hit back through Zian Flemming with seven minutes remaining.
An onslaught followed but City dug deep and came away with three points, in no small part to a Hanley goal-line clearance deep in injury time.
Millwall: Long, McNamara, Cresswell, Cooper, Wallace (Malone 88), Honeyman (Voglsammer 68), Leonard (Evans 88), Burke (Esse 68), Flemming, Saville (Watmore 68), Bradshaw.
Unused subs: Bialkowski, Hutchinson.
Goals: Bradshaw (20), Flemming (83)
Bookings: Leonard (12), McNamara (66)
Norwich City: Gunn, Aarons (McCallum 90), Hanley (C), Gibson, Giannoulis, Sørensen, McLean, Sara (Núñez 87), Idah, Hernández (Omobamidele 87), Pukki (Marquinhos 90).
Unused subs: Krul, Tzolis, Gibbs.
Goals: Sørensen (37), Own Goal (55), Sara (65)
Bookings: Hernández (35), Gibson (79), Aarons (88)
HT: 1-1
FT: 2-3
Venue: The Den
Referee: Graham Scott
Attendance: 18,785