Paul Robinson scored his first League goal at The Den for over two years as Millwall dented Swansea City's Play-Off hopes with a comfortable 2-0 win.
Neil Harris bagged the second for Willie Donachie's side with a perfeclty despatched penalty on 67 minutes as Millwall brushed aside Swansea's 10-men with ease.
Lions boss Donachie made two changes to the side beaten at Port Vale, with Ryan Smith coming in for his full first-team debut and Chris Hackett returning to the starting line-up.
But any hopes Millwall had of settling into their stride early on were disrupted when top scorer Darren Byfield was stretchered off in the opening minute after a crunching, but fair, collison with Swans' defender Dennis Lawrence.
Poul Hubertz stepped off the bench no sooner had he taken his place on it, and within nine minutes referee Rob Lewis had reached for his book to yellow card Swans' skipper Alan Tate for a clumsy challenge on the Lions striker.
On 21 minutes, referee Lewis was reaching for his book for a second time following Tate's lunging tackle on Smith, and the official had no option other than to send the visiting player off.
That seemed to spark both the home crowd - and players - into action, and within seconds Harris sent a flicked header inches wide of the post from Dave Brammer's cross.
The lively Smith, who had started on the right flank but switched to the left early on, became more influential as the game progressed, and his trickery caused all sorts of problems to the visiting defence.
It was following another piece of skill by the winger that Millwall earned a 28th-minute corner. Brammer's delivery was only half-cleared and Danny Senda sent a stinging effort a foot wide of the post.
Millwall finally made the breakthrough just past the half-hour mark when Smith's close control enabled the youngster to work an opening and send over a cross that bounced off the top of the bar, Hubertz headed back across goal and there was Lions skipper Robbo to slide home with a cool finish from six yards for his first home League goal since 6th March 2005.
Tony Craig, who produced an excellent display at left-back, combined well with Smith nine minutes before the break to set up Harris, only for the striker's effort to be blocked by former Lions keeper Willy Gueret.
Harris again tested the visiting goal on the stroke of half-time, on this occasion his deft chip dropping agonisingly wide of the mark.
Swansea boss Roberto Martinez made a couple of changes at the break, bringing on Lee Trundle and Richard Duffy in a bid to add some potency to their attack.
But Lions boss Donachie responded after 55 minutes, introducing Marvin Elliott for Hackett - a move which saw The Lions raise the tempo once more.
Hubertz headed over from a deep Senda delivery and then the striker should have done better when he was clear through on 63 minutes, but went for the glory himself when both Smith and Harris were in arguably better positions, and the big Dane was ultimately crowded out on the edge of the area.
However Millwall didn't have to wait that much longer for a second - and deserved goal.
When Craig played Harris through down the left, the striker cut into the area before he was sent sprawling by an outstretched boot.
Chopper picked himself up, dusted himself down and slotted home a perfect penalty, with the power and precision giving Gueret no chance as the ball flew into the bottom right-hand corner.
Chopper was desperately close to adding his second, and Millwall's third, barely four minutes later. Brammer's quick thinking from a freekick found Harris, who in turn found Hubertz, and the latter's cross was met by Chopper, whose header glanced just the wrong side of the post.
Harris was denied yet again two minutes from time when Gueret did well to get down low to hold the ball after Chopper had connected powerfully with another cross from impressive debutant Smith.
Other than a couple of tame long-range efforts that barely tickled the gloves of Lions keeper Lenny Pidgeley, Swansea looked anything but a side within touching distance of the Play-Offs.

Millwall: Pidgeley, Senda, Craig, Dunne (Ardley, 78mins), Robinson, Shaw, Brammer, Smith, Byfield (Hubertz, 1min), Harris, Hackett (Elliott, 55mins). Subs not used: Day, Ashton.
Booking: Brammer (50mins)
Scorers: Robinson (31mins), Harris (67mins, pen)

Swansea City: Gueret, O'Leary, Tate, Iriekpen, Britton (D. Duffy, 71mins), Abbott (Trundle, 46mins), Painter, Robinson, Lawrence, Butler, Craney (R. Duffy, 46mins). Subs not used: Williams, Oakes.
Bookings: Tate (9mins), Painter (76mins)
Sending off: Tate (22mins)

Ref: Rob Smith
Att: 9,249 (Away 716)