Tom Bradshaw scored the only goal of the game as Millwall's red-hot away form continued with a 1-0 win at Derby County in the Sky Bet Championship on Saturday afternoon.
The striker netted his eighth goal of the campaign midway through the first-half to give The Lions a third win in four on the road.
Gary Rowett opted to name the side side for the visit to Pride Park, with the only change coming on the bench as Shane Ferguson returned from injury to replace James Brown.
The home side started the afternoon on the front foot, but were unable to muster even a half-chance - Chris Martin's wild flick over the crossbar the closest they came.
With 11 minutes on the clock Bradshaw closed down the Derby defence and attempted to send Jed Wallace through on goal, but the striker's pass was too heavy and easily cleared. Jon Dadi Bodvarsson then carried the ball and fed The Lions' top scorer, but his shot was weak and saved by Ben Hamer.
Mahlon Romeo then found space down the right-hand side to cross but it was inches too far for the boot of Bradshaw. Gaining more and more of a foothold in the game as time went along, Millwall then forced consecutive free-kicks on either side of Derby's penalty area - one through a mazy run down the wing from Jake Cooper - but they came to nothing.
There were 25 minutes played, however, when a Millwall chance did come to something, and it came through the right boot of Bradshaw, who thumped an effort past Hamer to give The Lions the lead.
Two minutes later it should have been two, but as a deep cross from Romeo at the back post, his effort skidded wide of the post. At the other end, Duane Holmes had an attempt for The Rams, but it sailed comfortably over the crossbar.
Pride Park was becoming increasingly frustrated with their team's inability to move the ball forward at pace, but they did have the ball in the net four minutes before the half-time break; assistant referee Marc Perry, however, raised his flag for offside.
Tom Lawrence carried the ball down the left-hand side for Derby early in the second-half and squared for ex-Lion Martyn Waghorn, but the striker fired wide from just a few yards out.
The Lions' tails were still up as the hour-mark approached, but The Rams were now much more speedy in their attacks and attempts to fashion a chance for the equaliser - there were shouts for a penalty-kick after Waghorn tumbled in the area on 63 minutes, but referee Chris Kavanagh was unmoved.
The home side were now in the ascendancy and Jayden Bogle's cross-cum-shot troubled Bartosz Bialkowski, but the Pole managed to claw the ball to safety, before Waghorn flashed a shot wide with 76 minutes played.
There was nearly a very fortunate equaliser for Derby 10 minutes from time, but after Bogle's cross took a wicked deflection, Bialkowski - despite seeing the ball very late - managed to get down and turn the ball behind.
Substitute Ben Thompson suffered what looked to be a nasty ankle injury blocking a cross just a couple of minutes from time and had to be replaced by Matt Smith, but The Lions survived five minutes of stoppage-time to notch another win on the road.
Derby County: Hamer, Forsyth (Jozefzoon 81'), Waghorn, Lawrence, Evans, Martin, Holmes (Whittaker 88'), Lowe, Davies, Bogle, Knight (Dowell 74'). Subs not used: Roos, Wisdom, Bielik, Malone.
Millwall: Bialkowski, M. Wallace, Hutchinson, Cooper, Williams, J. Wallace, Bradshaw (O'Brien 81'), Romeo, Pearce, Molumby, Bodvarsson (Thompson 67' (Smith 88')). Subs not used: Steele, Ferguson, Mahoney, Skalak.
Scorer: Bradshaw 25'
Referee: Chris Kavanagh
Attendance: 26,272 (855)