Millwall's hopes of pulling off an FA Cup upset at the expense of Premier League Birmingham City were quashed as Alex McLeish's men cruised into the Fourth Round.
The Blues raced into a 3-0 lead at the halfway stage and although The Lions were handed a 50th-minute lifeline, Steve Morison's penalty was saved by visiting keeper Maik Taylor.
Sub Cameron Jerome then netted with his first touch with 19 minutes remaining to put the result beyond doubt, with Danny Schofield's injury-time effort scant reward for a spirited Millwall display.
Quite simply, although The Lions proved more than a match for their top flight opponents in the first two thirds of the pitch, it was Birmingham's Premier quality that showed where it mattered most - in front of goal.
Whilst playing some nice football themselves at times, Kenny Jackett's men were ruthlessly punished on three of the four times Birmingham created chances in the first half.
"We needed the first goal but didn't get it," rued Jackett. "Birmingham were clinical, but they were poor goals to give away. Saying that we created a lot of chances and played well. There were lessons learned."
A bright opening saw James Henry lash wide and then a promising move broke down when the winger lost possession on the edge of the danger zone as Millwall made the early running.
The Lions created and wasted a glorious chance to break the deadlock just before the quarter-hour mark.
Tamika Mkandawire and Neil Harris combined to set top scorer Morison clear on the right. He in turn surged forward, but for some reason went wider than he needed and from a tight angle sidefooted agonisingly wide of the far post.
That miss proved costly and within two minutes Matt Derbyshire, capitalising on hesitency in the home rearguard, grabbed the first of his brace, despatching a clever chip that looped over the head of Danny Shittu and into the back of the net.
Birmingham doubled their tally on 26 minutes when Tony Craig was penalised for a foul just outside the penalty area. David Murphy stepped up and planted the ball into the top right corner with a sublime left-foot free-kick that left David Forde grasping at thin air.
It was nearly 3-0 when Craig Gardner's long range effort was hacked clear by Craig just moments later.
At the other end oppositing keeper Taylor flapped at a Henry delivery, the ball fell for Morison with his back to goal, but the striker's overhead kick dropped wide.
Henry then lashed the ball into the side netting and skipper Paul Robinson saw his header deflected for a corner as The Lions tried to get a foothold.
Millwall were left with a second-half mountain to climb seconds before the break, however, when further indecision in the home rearguard was seized upon by Derbyshire, who slotted home Birmingham's third.
Jackett's men were handed a golden opportunity to reduce the deficit five minutes after the restart when Neil Harris was sent tumbling in the box. Up stepped Morison, but his spot-kick was comfortably parried by Taylor.
The Lions must have known it really wasn't going to be their day barely 90 seconds later when Morison drove forward into the box, Henry's piledriver was blocked and Harris somehow scooped over from barely six yards.
Boss Jackett brought on Schofield and Kevin Lisbie, but it was Birmingham who threatened again, this time Jean Beausejour's 20-yard shot deflected against the woodwork.
Lisbie swept a neat pass from Jack Smith over from a central position as The Lions threatened again, but it was Birmingham who struck for a fourth time with 19 minutes remaining.
Jerome perhaps best summed up the crucial difference between the two teams on the day when, with his first touch after coming on as a substitute, he powered home a header at the far post following a quick break.
Not only did Millwall now face a four-goal deficit, but for the final eight minutes they were a man short as well when skipper Robbo was forced off injured.
Even so, and to their immense credit, they kept plugging away and grabbed what was scant consolation for their efforts in the first minute of injury time courtesy of a thumping finish from Schofield following more good work by Smith.
By then the damage had been done and it is Birmingham who now look forward to Sunday's Fourth Round draw with interest.
Millwall: Forde, Smith, Craig (Schofield, 60mins), Abdou, Robinson, Shittu (Ward, 72mins), Barron, Mkandawire, Harris (Lisbie, 60mins), Morison, Henry. Subs not used: Mildenhall, Grabban, Hackett, Marquis.
Scorer: Schofield (90+1mins)
Birmingham City: Taylor, Murphy, Gardner, Derbyshire (Phillips, 69mins), Dann, Zigic (Jerome, 69mins), Parnaby, Hleb (Fahey, 61mins), Beausejour, Mutch, Jiranek. Subs not used: Doyle, Johnson, Larsson, Madera.
Scorers: Derbyshire (16, 44mins), Murphy (26mins), Jerome (71mins)
Ref: Lee Probert
Att: 9,841 (away 773)