Matt Smith scored the only goal of the game as 10-man Millwall kept up their unbeaten start to the season with a 1-0 win over Sheffield Wednesday at The Den in the Sky Bet Championship on Saturday afternoon.
In a game that saw Jed Wallace shown a straight red card shortly before the half-time break, Smith arrived at the back post to nod home Connor Mahoney's corner with 37 minutes gone.
The second-half produced a heroic performance, as The Lions defended for their lives, backed by 13,000-strong in SE16.
Neil Harris chose to keep the same squad from the 1-0 opening-day win over Preston North End, meaning there were returns to the starting XI for Mahlon Romeo, Alex Pearce, Jake Cooper, Jed Wallace, Shaun Williams, Ben Thompson, Mahoney and Smith.
Despite the atmosphere ramping up at both ends of the ground, action on the pitch was of a quiet nature until the 12th minute, but Connor Mahoney's cross was too long for Murray Wallace. A fortunate bounce then played Wednesday in for their first chance on goal of the afternoon, but the offside flag scuppered any attempt, despite Bialkowski saving Adam Reach's effort.
The table-toppers then had a spell of possession and fashioned a chance after the tricky Kadeem Harris fed the ball to Liam Palmer, but Bialkowski was equal to the shot, parrying it behind for a corner-kick - one that was eventually cleared to safety.
After more Wednesday pressure, Reach then tried his luck - as has been seen before - from around 35 yards out, but fortunately, the ball landed on the top of the net rather than in it.
Jed Wallace then fizzed a cross into the box as Millwall looked to get themselves back on top, but the boot of Julian Borner cut any chance of the onrushing Lions frontmen's opportunity to open the scoring.
Mahoney's corner then found the unmarked Williams, but the midfielder fluffed his lines, but after the ball found its way behind and out for another corner, this time, the winger's deep kick was nodded home by Smith for his second goal of the season and first at The Den.
After a brief stoppage, The Owls were the next ones to try their luck on goal, but Jacob Murphy's outside-of-the-boot curler sailed over Bialkowski's crossbar.
Shortly before half-time, The Lions were reduced to 10 men after Jed Wallace lunged in - consultations between referee Gavin Ward and his linesman took place, with Ward then brandishing a straight red card.
With their man advantage, Wednesday began the second-half on the front foot and nearly equalised through Murphy, but after tricky work from Harris, the visiting man's shot was straight at Bialkowski. It was then the turn of Steven Fletcher, but the stopper stood tall once more to prevent an equaliser.
At the other end, set-pieces were becoming Millwall's main threat, and after Mahoney swung another one into the box, Cooper rose, but he headed over the crossbar.
Tom Bradshaw was brought on to lead the line in place of goalscorer Smith, but it was fellow attacker O'Brien who had the next chance - however, his long-range effort was tipped over by Keiren Westwood.
Around 13,000 Lions fans inside The Den were backing their team to the hilt, acting as the 11th man, with The Lions blocking shots and defending heroically, most notably through Romeo, who superbly timed his tackle to cannon the ball off Harris and out for a goal-kick.
Bialkowski then used his frame once more, this time to stop substitute Barry Bannan's goal-bound effort, before captain Pearce was the next one to stop Wednesday in their tracks, clearing under pressure from Fletcher - sub Jordan Rhodes then glanced wide.
Relentless pressure from The Owls continued, with Sam Hutchinson having a go at goal, Rhodes heading over and Borner doing the same, before referee Ward blew time to an almighty roar as The Lions secured a fantastic victory.
Millwall: Bialkowski, M. Wallace, Cooper, Williams, J. Wallace, Thompson, Smith (Bradshaw 52'), Romeo, Pearce, Mahoney (Leonard 74'), O'Brien (Ferguson 83'). Subs not used: Steele, Shaun Hutchinson, Bodvarsson, Skalak.
Scorer: Smith 37'
Sent Off: J. Wallace
Sheffield Wednesday: Westwood, Palmer (Luongo 59'), Lee (Rhodes 65'), Harris, Fletcher, Borner, Murphy, Lees, Reach, Sam Hutchinson, Iorfa. Subs not used: Dawson, Fox, Bannan, Nuhiu, Odubajo.
Referee: Gavin Ward
Attendance: 15,017 (2,177)