Millwall moved into the automatic promotion places with a four-goal rout of struggling Gillingham.
The Lions took full advantage of defeats by Swindon and Charlton to leapfrog into second spot, one point clear of third-placed Leeds United.
It was a stroll in the sunshine for Kenny Jackett's men, and to complete a highly satisfactory afternoon, top scorer Steve Morison has now passed the cut-off point for accumulating 10 bookings and will now be available for Tuesday's clash at Yeovil Town.
Morison was partnered up front by Shaun Batt, one of the first two changes boss Jackett made to his starting line-up in five games.
Right-back Alan Dunne was ruled out with a slight groin strain sustained in training on Friday so Jack Smith stepped in for his first appearance since February.
The Lions went into the game not only aiming to extend their 13-match unbeaten run at The Den, but to also secure a 14th win in 17 starts.
Struggling Wycombe Wanderers were the last team to leave SE16 with all three points way back on 22nd November, but two goals in either half from Millwall made sure of the points in sunny south east London.
It took The Lions just 26 seconds to register their first shot on target courtesy of Chris Hackett's low drive from the left.
Danny Schofield then picked up a fine left-foot pass from Smith, chested down and drove an effort straight at Gills' keeper Alan Julian as the home side prised and probed for the crucial opening goal.
It duly arrived on 26 minutes when neat interplay by Liam Trotter and Schofield set up Batt, who fired home crisply into the bottom right corner.
The Lions doubled their tally nine minutes later with a looping 20-yard volley from left-back Tony Craig with keeper Julian rooted to the spot.
Millwall nearly handed Gills a lifeline in first-half injury-time when a mix-up between Robinson and Smith saw Rene Howe nip in, only to see his low shot well held by the diving David Forde.
Having established a 2-0 goal cushion, Jackett replaced Morison with Harris at the start of the second half, whilst Gills' manager Mark Stimson introduced Josh Gowling for Darren Dennehy.
Stuart Lewis mustered the visitors' first noteworthy effort of the half a couple of minutes after the break with a smart shot on the turn that flashed a yard wide.
Gillingham were forced to make another substitution on 50 minutes following an accidental clash between keeper Julian and Garry Richards that left the defender unable to continue.
Julian was involved in the thick of the action again on 56 minutes, this time with a poor pass to Barry Fuller. Batt was on the loose ball like a flash, with his subsequent cross cleared from Harris' toes.
A perfectly timed tackle by Robinson thwarted Andy Barcham as he broke into the penalty area as Gills tried, but failed, to build up a head of steam.
Any hopes of a second-half fightback were shattered by a stunning third goal for The Lions on the hour mark.
Schofield picked up the ball near the halfway line and weaved past a plethora of opposition players with some dazzling footwork before despatching a sublime left-foot curler that left Julian grasping at thin air - and the home fans gasping at the sheer brilliance of the midfielder's goal.
Millwall made it 4-0 just six minutes later courtesy of Harris' header from close range after Robinson had flicked on Craig's corner from the right.
Thereafter it was a real stroll for The Lions, who enjoyed long spells of possession against a spirited, but ultimately out-classed Gillingham.
Millwall: Forde, Smith, Craig, Abdou, Robinson, Ward, Schofield, Trotter (Barron, 79mins), Batt (Obika, 74mins), Morison (Harris, 46mins), Hackett. Subs not used: Sullivan, Laird, Alexander, Frampton.
Scorers: Batt (26mins), Craig (35mins), Schofield (60mins), Harris (66mins)
Gillingham: Julian, Fuller, Nutter, Lewis, Richards (Bentley, 50mins), Jackson, Barcham, Miller, Jackman, Howe (Maher 75mins), Dennehy (Gowling, 46mins). Subs not used: Royce, Dickson, Oli, Weston.
Booking: Miller (4mins)
Ref: Mark Haywood
Att: 13,174 (away 1,112)