MILLWALL moved within one point of the League One play-offs places after thumping Bristol Rovers 4-0 at The Den.
Goals from Aiden O'Brien, Shaun Williams, Lee Gregory and Harry Smith saw Millwall grab all three points in what was a comprehensive victory against side sitting in fifth before kick-off on Saturday afternoon.
Steve Morison again missed out through injury with Shaun Hutchinson also absent from the match-day squad.
Greg Wylde came onto the bench after setting up Fred Onyedinma's equalising goal against the Hatters last time out.
In a quiet opening ten minutes, Peter Hartley had the vistors' best chance when his header from a Chris Lines' corner was cleared off the goal line by Ben Thompson.
Prior to that, Joe Martin saw two efforts blocked inside the area from a corner before Byron Webster's cross was blocked and cleared.
Five minutes later, the away side were on the attack again, this time with Matty Taylor firing just over from the edge of the box.
The game changed course on 14 minutes when Bristol Rovers were reduced to ten men.
Daniel Leadbitter was given his marching orders for being the last man after he had fouled O'Brien on the edge of the box.
The resulting free-kick from Martin hit the Rovers wall but Millwall started to put considerable pressure on the visiting defence.
On 19 minutes, Harry Smith came astonishing close to scoring on his league debut after his looping header was clawed away by Kelle Roos in the Gas goal.
Millwall laid siege on the Rovers goal after the dismissal, and on 23 minutes, they deservedly took the lead.
Gregory's second attempt at a snap shot was parried by Roos right into the path of O'Brien and the winger obliged by side-footing home from all of two yards to settle any pre-existing nerves.
From there, Harris' men took the game by the scruff of the neck, despite having many more clear-cut chances on goal.
The Lions were controlling the game and doing well in possession to vary up their approach play going into the break a goal to the good.
Webster twice cleared early second half danger as the Lions broke with Smith eventually curling an effort at Roos.
At the other end, Rovers won a free-kick on the edge of the box but it was eventually cleared by Craig as the Lions looked to continue their strong hold on the game despite only being one goal up.
On 52 minutes, Hiram Boatang dashed past Thomson and Webster with ease before his low, close-range effort was parried out for a corner by Jordan Archer in the Lions goal.
Neither side were letting up as the hour mark approached, with the atmosphere going up a notch.
Rovers worked hard to loosen the host's grip on a game but the Lions maintained their discipline and shape.
Millwall were being afforded time and space around the visitor's penalty area.
An example of that being Gregory with time and space to curl a ball towards Williams who sent a diving header wide despite pressure from Lockyer in the Bristol defence.
The Lions took advantage of such a luxury with 25 minutes left, as their lead was doubled.
Substitute David Worrall played a ball into Gregory inside the box was held up under pressure before the striker laid the ball off to Williams on the edge of the box before the midfielder rifled home into the bottom right-hand corner.
It was a lead that in no way flattered the Lions; they looked solid, compact and in control during large spells of the match.
It was 3-0 four minutes after when Gregory found the back of the net after a ball in from the left was headed into his path by Smith.
The Lions number nine then chested the ball down before thumping a volley past Roos to all but secure the three points for Harris' side.
Smith came close for a second time to scoring on his league debut when the Rovers keeper did well to save from a close range header.
However, Smith was not to be denied and the young Lion finally scored on his league debut.
Rovers made a meal of possession and the ball eventually found Smith lurking on the penalty spot as he stroked the ball past an on-rushing Roos to seal all three points and cap off a fine league debut as a resolute Millwall side moved up to eight in the table.