Millwall were defeated 1-0 by Derby County in the Sky Bet Championship on Saturday afternoon.
Jason Knight struck the winner in the 69th minute to give The Rams all three points.
On the day 2,000 fans were welcomed back inside the stadium, Gary Rowett opted to name a 4-2-3-1 formation against The Rams, with Matt Smith in attack and Jed Wallace, Ben Thompson and Shane Ferguson behind him. Ryan Leonard and Ryan Woods anchored the midfield, whilst Mahlon Romeo, Shaun Hutchinson, Jake Cooper and Murray Wallace sat in front of Bartosz Bialkowski.
Youngsters Tyler Burey and Hayden Muller, meanwhile, were joined on the substitute's bench by George Alexander.
Roared on by 2,000 fans - and what a great sight it was - the game got underway with The Lions creating most of the attacking play. Derby's first attempt came in the 10th minute and through Kamil Jozwiak after The Rams were given a dubious free-kick on the halfway line, but the shot went wide of Bialkowski's near post.
Two minutes later, Jed Wallace took Smith's lay-off in his stride and showed determination and spirit to beat his marker, but his left-footed effort was well saved by David Marshall. At the other end, on 17 minutes, Matthew Clarke got his head on the end of a Derby free-kick, but the ball sailed over the crossbar.
At the midway point of the half - and after soaking up some Derby pressure - a one-two between Jed Wallace and Romeo resulted in the latter crossing for Thompson, but his side-footed volley went over. Ferguson had a shot blocked on the edge of the penalty area and a free-kick pinballed into the arms of Marshall as The Lions continue to probe for the opening goal, although it could have Derby who scored it as Duane Holmes received the ball on the edge of the area - solid defending from Murray Wallace, however, kept things goalless.
Graeme Shinnie struck over as the first-half clock wound into its final five minutes, with the second-half action springing into life on 54 minutes as Jed Wallace shurgged off the close attentions of his marker - his cross, however, was tamely headed into the hands of Marshall by Smith.
Shinnie fired high, wide and not so handsome two minutes later, before Ferguson's free-kick was drilled into the wall and Leonard shot wide just before the hour-mark. Millwall kept up their attempts to find the back of the net from there and nearly found it through the head of Cooper, but he glanced wide from Ferguson's corner.
On 69 minutes, though, The Rams were the ones to take the lead after Knight was quickest to react in the penalty area after a knockdown at the far post.
The lack of urgency in The Lions following that goal was showing - and Derby could have notched a second with eight minutes remaining, but Bialkowski was able to gather Clarke's header at the back post.
From there, The Rams were able to negotiate four minutes of stoppage-time with relative ease to wrap up the victory.
Millwall: Bialkowski, M. Wallace, Hutchinson, Cooper, J. Wallace, Thompson (Parrott 58'), Smith (Bodvarsson 76'), Ferguson (Burey 77'), Romeo, Leonard (Williams 90'), Woods. Subs not used: Fielding, Pearce, Skalak, Alexander, Muller.
Derby County: Marshall, Forsyth, Shinnie (Bird 64'), Bielik, Jozwiak (Wisdom 90+3'), Byrne, Kazim-Richards (Buchanan 86'), Clarke, Holmes (Waghorn 64'), Davis, Knight. Subs not used: Roos, Lawrence, Ibe, Sibley, Stretton.
Scorer: Knight 69'
Booking: Shinnie, Bielik, Waghorn, Kazim-Richards, Byrne
Referee: Darren England