Spectacular goals in either half from Steve Morison and Theo Robinson sent The Lions to their first home win since August as they swept aside Derby County at The Den.
Morison ended his five-game barren run in front of goal with a stunning 20-yard opener on 11 minutes before Robinson sent a bullet header into the roof of the net for Millwall's second on 49 minutes.
Despite a late spell of pressure from Nigel Clough's Rams that was comfortably dealt with, this was as good a performance from Kenny Jackett's side as any this season.
"We did everything we didn't do on Tuesday night," enthused Kenny.
"We started with a good tempo, moved the ball around well and created chances.
You could see that Derby had confidence and they put us under a bit of pressure near the end, but we coped well and I'm pleased we got through it for a great win."
Lions boss Jackett made five changes to the team beaten at home by Portsmouth on Tuesday evening in a bid to elicit a positive response from his side.
The fluidity and attacking enterprise that had become, by Jackett's own admission, somewhat predictable returned with aplomb as Millwall produced a performance full of zip and vigour.
Defender Danny Shittu, who signed on a three-month contract on Friday, had an immense debut from his first powerful headed clearance on 26 seconds to the 77th minute, when he was replaced by Darren Ward.
It took two minutes for The Lions to register their first chance of the game when great skill and combination play by Scott Barron and Danny Schofield picked out Robinson. Although he was in a decent central position, James Henry had sprinted forward unmarked on the overlap and looked better placed to have a shot. Unfortunately Robinson opted to have a go himself, and his effort was comfortably held by Frank Fielding in the Derby goal.
By 11 minutes Millwall's early pressure paid off, and what a handsome effort it was too.
Liam Trotter held off a couple of Derby players on a powerful forward run, fed the ball to Morison who swept home first time with a crisp effort beyond the reach of keeper Fielding.
Trotter was again in the thick of the action with a sublime piece of footwork to set up Alan Dunne, but the latter's effort flew wide.
Henry then sent a looping header narrowly over after Barron somehow squeezed a cross over from the tightest of angles on the left.
Robinson, who worked tirelessly all afternoon, twice had efforts blocked as The Lions continued to press for a second goal.
Dean Moxey cleared another Robinson shot before Trotter scuffed wide from 18 yards after Morison had flicked-on.
Lions keeper David Forde had one save to make during the first half, diving low to his right to push Moxey's drive round the post for a corner as Derby enjoyed a spell of sustained pressure just before the break.
However any hopes The Rams had of forcing an equaliser early in the second half were dashed just four minutes after the restart. A slick move involving Dunne and Henry sent Morison away down the right flank, he in turn despatched a delicious delivery met by the diving Robinson, whose bullet header flew into the top corner.
It could have been three a couple of minutes later when Schofield and Barron, who linked superbly on the left flank throughout, once again combined well. On this occasion, Schofield's pass picked out Barron as he raced into the danger zone, and the latter's cross-shot was cleared off the line for another corner, one of eight chalked up by The Lions.
Derby boss Clough introduced Luke Moore and Tomasz Cywka for Alberto Bueno and Robbie Savage, with Bueno booked just seconds beforehand for an awful studs-up challenge on skipper Paul Robinson.
Shaun Barker headed narrowly wide from a corner, with Lions keeper Forde stranded as he struggled to cope with the sun shining straight in his eyes.
Jimmy Abdou and Ward entered the fray on 77 minutes for the tiring Shittu and Theo Robinson, leaving Morison as the lone target man up front for Millwall.
Although the visitors enjoyed more of the possession in the final quarter of an hour, Forde was well protected by his defence and in fact it was Millwall who could have added a third goal in the first of five minutes of injury-time, but his fierce angled drive flashed wide of the post.
Millwall: Forde, Dunne, Barron, Trotter, Robinson, Shittu (Ward, 77mins), Schofield, Mkandawire, Morison, T.Robinson (Abdou, 77mins), Henry (Hackett, (90+1mins). Subs not used: Mildenhall, Craig, Lisbie, Marquis.
Scorers: Morison (11mins), T.Robinson (49mins)
Derby County: Fielding, Brayford, Green, Barker, Leacock, Savage (Cywica, 64mins), Kuqi, Commons, Bailey, Moxey (Roberts, 86mins), Bueno (Moore, 64mins). Subs not used: Anderson, Pringle, Doyle, Atkins.
Booking: Bueno (63mins)
Att: 12,024 (away 1,090)