|Morison 30, Jackson pen 88||Venue: The Den
|Ibe 18, Shinnie 35, Zigic 52|
MILLWALL hit rock bottom after a disastrous defeat at home to Birmingham.
The Lions slumped to the foot of the Championship table as the Blues ran out deserved winners under the floodlights at The Den.
Steve Morison cancelled out Jordan Ibe's opener but Andy Shinnie and Nikola Zigic scored close-range headers either side of the break to put the visitors in control.
Simeon Jackson converted a late penalty but Millwall could not find an equaliser.
Ian Holloway opted for a change of formation following the 2-1 defeat at Leeds.
The Lions lined up in a 3-4-3 formation with a back three of Alan Dunne, Paul Robinson and Shane Lowry, while Ryan Fredericks, Morison and Jimmy Abdou returned to the side.
DJ Campbell, who scored at Elland Road on Saturday, was also named in the starting XI.
Millwall started the game at a quick tempo and Morison forced visiting goalkeeper Darren Randolph into an important double save in the 13th minute.
From the resulting corner, Campbell headed straight into the arms of Randolph after Scott McDonald's corner had been nodded back across goal.
Morison should have broken the deadlock when Owen Garvan's miscued shot fell perfectly to him inside the area, but the striker sliced his shot wide.
And as is now becoming a weekly occurrence, the Lions swiftly fell behind at the other end against the run of play.
Martyn Woolford and Dunne both failed to clear and Liverpool loanee Ibe squeezed an accurate shot into the corner despite David Forde getting a firm hand on the ball.
But Millwall hit back in the 30th minute when McDonald's floated cross-field pass picked out Morison, whose shot from a narrow angle deflected in off a defender.
The Lions were not level for long, however, as Shinnie barged past Lowry to head in Tyler Blackett's first-time cross from the left flank.
That goal exposed the frailties of a three-man defence and Holloway soon reverted to a flat back four, with Fredericks slotting in at right back.
Shortly before half time, Fredericks was felled on the edge of the area but Garvan curled the free kick narrowly over the bar.
At half time, Holloway replaced Lowry and Dunne with Jackson and Mark Beevers.
The second period began in controversial fashion as Millwall were denied a penalty after Paul Robinson appeared to handle Campbell's cross near the byline.
And moments after referee Scott Mathieson had dismissed the Lions' appeals, Zigic nodded in Chris Burke's cross to make it 3-1.
Millwall's immediate response was limited to Garvan's scuffed shot which brushed the side netting on its way wide.
Zigic dispossessed Woolford, who was playing as a left back, in the 79th minute and squared for Shinnie, but he blasted over from inside the area.
The Lions' evening was then summed up when sub Stefan Maierhofer crossed for Garvan, who somehow headed wide of an open goal.
Jackson won and scored a late penalty after he was bundled over by Aaron Martin but Birmingham saw out four minutes of added time to claim the three points.
Wins elsewhere for Charlton and Barnsley ensured Millwall dropped to 24th in the table.