Millwall were 3-1 winners over Birmingham City in the Sky Bet Championship at The Den on Saturday afternoon.
Murray Wallace gave The Lions a 10th-minute lead in South London, before Tom Bradshaw doubled the advantage before half-time.
Troy Deeney halved the deficit after the break, but a confident finish from George Evans secured all three points in SE16.
Gary Rowett made three changes from the side which were defeated 2-1 by Hull City last weekend, with Jake Cooper, Scott Malone and Evans coming into the starting line-up at the expense of the injured Daniel Ballard, plus Sheyi Ojo and George Saville, who both dropped to the bench.
Neat footwork from Benik Afobe gave The Lions the first opportunity of the game just two minutes in, but a wasteful free-kick saw Malone and then Jed Wallace fail to trouble Neil Etheridge.
After a stoppage in the sixth minute to remember Arthur Labinjo-Hughes, The Lions returned to the attack and sent a couple of inviting crosses into the area, but the Birmingham defence were able to clear.
Tom Bradshaw was the next to try and find a Millwall man in the box from the right-hand side, but Kristian Pedersen was well-placed to clear behind - however, from the resulting corner came the opening goal, as a short corner was worked to Evans; his effort was blocked, but Murray Wallace was on hand to mop up and fire home.
The Lions' confident play continued following the goal, with a move ending in a corner on 16 minutes that Malone sent directly into the side-netting. Cooper then headed a Malone free-kick goalwards, but that was claimed by Etheridge, before an acrobatic attempt by Afobe went just wide of the near post.
The Blues spent the midway point of the half looking to gain a foothold in the game, but they were unable to test Bartosz Bialkowski for the first time until the half-hour mark, when Scott Hogan's tame effort was easily gathered by the stopper.
Deeney's through-ball to Hogan had to be snuffed out by Cooper just two minutes later as the visitors looked for the equaliser, before Marc Roberts headed a corner wide. With four minutes remaining in the first-half, though, The Lions doubled their lead as Bradshaw thumped home a Malone corner with his head from the edge of the six-yard box.
The second-half got underway with a smart interchange of passing, mainly involving Jed Wallace, moving the ball upfield for The Lions, but the number seven's shot was blocked behind. Afobe then hassled Marc Roberts into a mistake on the touchline, forcing the defender to bring him down and take a booking with 50 minutes played, but Cooper could only nod Jed Wallace's free-kick over.
There were 53 minutes on the clock when a sublime one-two between Bradshaw and Jed Wallace led to the former being able to pull the trigger from just inside the area, but a strong stop from Etheridge kept the scoreline at 2-0.
At the other end, Millwall's defence blocked efforts from Deeney and Riley McGree, but The Blues were able to reduce the arrears on 56 minutes as Deeney broke through to fire past Bialkowski.
As the visiting crowd got behind their team, The Lions responded and looked to work a way through to goal through the aforementioned combination of Bradshaw and Jed Wallace on the hour mark, but once again the former was foiled by the defence. Jed Wallace then showed determination to break down the right and cross, but Etheridge was able to claim, despite spilling the ball and Malone closing in.
A neat passage of play then ended with the ball at the feet of Afobe with 68 minutes gone, but Etheridge was once more the Birmingham hero as he parried the striker's effort wide.
With The Blues pushing for a second, a huge sigh of relief went up around three sides of The Den on 73 minutes as Millwall made it three. Danny McNamara's persistance saw him shake off his marker and slide the ball across for the awaiting Afobe and Evans, with the latter bending a stylish effort into the top corner.
It could have been four three minutes later, but as Jed Wallace broke through and found his effort blocked, Malone's follow-up was tipped over by the back-pedalling Etheridge for a corner. At the other end, Pedersen could have made the last 10 minutes uncomfortable for The Lions, but his header from a corner whistled just past the post.
A minute from time, after Bialkowski had to rush out to clear from danger, Birmingham substitute Chuks Aneke could have set up a grandstand finish, but he sent his shot wide of the far post.
Afobe then could have had the last laugh in four minutes of stoppage-time, but after he shrugged off his marker, his effort was stopped by Etheridge.
Millwall: Bialkowski, McNamara, M. Wallace, Hutchinson, Cooper, J. Wallace (Kieftenbeld 83'), Bradshaw (Bennett 89'), Malone (Pearce 86'), Afobe, B. Mitchell, Evans. Subs not used: Long, Smith, Ojo, Saville.
Scorer: M. Wallace 10', Bradshaw 41', Evans 73'
Birmingham City: Etheridge, Pedersen, Roberts, Hogan (Aneke 80'), Bela (Jutkiewicz 46'), McGree, James, Sanderson, Graham, Sunjic, Deeney. Subs not used: Trueman, Friend, Dean, Castillo, Hall.
Scorer: Deeney 56'
Booking: Pedersen, Roberts
Referee: Andy Woolmer
Attendance: 14,324 (2,152)