Super sub Jason Price stepped off the bench to hit a double whammy and knock AFC Wimbledon out of the FA Cup in an absorbing first round encounter.
Newly crowned World WBA heavyweight champion David Haye turned up to watch The Lions in action against their non-league opponents less than 48 hours after producing the performance of a lifetime to defeat Nikolay Valuev.
And the Bermondsey boxer, who received a rapturous ovation from The Den faithful, was delighted to watch Millwall march into the second round.
Boss Kenny Jackett was able to name an unchanged team for the fourth succcessive match, and although his men enjoyed the lions share of possession in the opening half, the home side were unable to break the deadlock.
Terry Brown's Dons, spurred on by nearly 3,400 fans, chased, harried and made life pretty uncomfortable to frustrate the home side, with Steve Morison's header (7mins) and a Neil Harris curler (24mins) both comfortably dealt with by visiting keeper James Pullen.
But there was little Pullen could do three minutes after the break when Morison's neat hooked ball played Harris through in a central position, and he made no mistake with a rasping left-foot shot into the back of the net.
Back came The Dons, and Jon Main was a whisker away from levelling on 51 minutes only to be denied by a great Tony Craig block, with the ball spinning a foot wide of the post.
At the other end Pullen was called into action, producing the save of the game - a sensational tip-over after Jimmy Abdou's shot had taken a wicked deflection and looked destined for the top corner.
A quick throw from Chris Hackett after 64 minutes picked out Harris, and his first-time left-foot shot flew over the bar as Millwall searched for a second goal.
Jack Smith tried his luck from distance and then Tony Craig was thwarted by an acrobatic save from the impressive Pullen as The Lions pressed.
But it was Price, a 68th-minute replacement for the hard-working Morison, who gave the home side some breathing space.
Abdou was sent sprawling by Elliot Godfrey on the left flank, Hackett whipped over a deep free-kick, the ball was half-cleared and there was Price to sweep home with his first touch.
Credit to Wimbledon who refused to roll over and when Lewis Taylor steered an angled drive into the bottom corner with 10 minutes remaining, the goal breathed fresh impetus into the visitors - and urgency into The Lions.
Danny Schofield restored Millwall's two-goal cushion with the goal of the night five minutes later - a peach of an effort from 16 yards after some delightful footwork from the former Yeovil man.
Schofield was again involved to finally see off a dogged Dons outfit, providing an inch perfect pass that picked out Price on the counter attack, and the sub nonchalently slotted home his second - and Millwall's fourth of the night to wrap up victory.
Millwall: David Forde, Alan Dunne, Jack Smith, Jimmy Abdou, Paul Robinson, Tony Craig, Danny Schofield, Marc Laird, Steve Morison (Jason Price, 68mins), Neil Harris (Dave Martin, 88mins), Chris Hackett. Subs not used: John Sullivan, Adam Bolder, Lewis Grabban, Darren Ward, Ashley Grimes.
Booking: Abdou (57mins)
Scorers: Harris (48mins), Price (71, 87mins), Schofield (85mins)
AFC WImbledon: James Pullen, Sam Hatton, Brett Johnson, Steven Gregory, Paul Lorraine, Alan Inns, Elliot Godfrey Derek Duncan, 72mins), Lewis Taylor, Danny Kedwell, John Main, Luke Moore. Subs not used: Jay Conroy, Seb Brown, Ben Judge, Ricky Wellard, Luis Chambers, Ross Montague.
Bookings: Gregory (45+1mins), Hatton (58mins)
Scorer: Taylor (80mins)
Ref: Scott Mathieson
Att: 9,453 (away 3,339)