Birmingham's Craig Gardner booked a League Cup final showdown against Arsenal as his extra-time goal sealed a 3-1 victory over West Ham in Wednesday's semi-final second leg that secured a 4-3 aggregate win.
Gardner, a boyhood Birmingham fan, capped an impressive fightback from Alex McLeish's side, who can now look forward to facing the Gunners at Wembley on 27 February in their first League Cup final appearance for 10 years.
When Carlton Cole scored midway through the first half at St Andrew's, West Ham were 3-1 up on aggregate after winning the first leg 2-1 at Upton Park. West Ham co-owners David Sullivan and David Gold, who previously owned Birmingham, must have been dreaming of Wembley as they watched at home.
But former West Ham midfielder Lee Bowyer levelled for Birmingham - whose only trophy was in this competition in 1963 - before Roger Johnson's header sent the tie to extra time and set the stage for Gardner to shatter the Hammers.
McLeish had handed a rare start to central defender Martin Jiranek in the absence of the injured Scott Dann, while West Ham were without suspended strikers Victor Obinna and Frederic Piquionne. Those absences didn't affect West Ham early on and they almost caught Birmingham on the counter-attack when a fine pass from Mark Noble allowed Zavon Hines a run at goal.
But Ben Foster, whose blunder had handed the Hammers their second goal in the first leg, was well placed to block the shot from a wide angle. Cole should have done better when he fired over from inside the area after meeting a ball over the top from West Ham defender Matthew Upson.
West Ham made the breakthrough in stunning fashion in the 31st minute. England striker Cole was allowed time and space to line up a long-range shot and he took full advantage as his fierce strike flashed past Foster into the net. It could have been worse for Birmingham when Johnson was relieved to see the ball hit the outside of a post after he deflected a shot past Foster.
But McLeish sent on Nikola Zigic for Derbyshire at half-time and the change revitalised Birmingham. Gardner nearly equalised in the 53rd minute when his drive hit the inside of a post and flew across the goal without crossing the line.
Bowyer gave Birmingham hope in the 59th minute when he lashed home a perfect half-volley after another Larsson corner wasn't cleared. West Ham were hanging on now and Green did well to turn aside a shot from Barry Ferguson which flew through a ruck of players.
Green tipped over a Cameron Jerome header from Larsson's corner but after 79 minutes Johnson brought Blues level with a powerful header from Bowyer's cross. Jerome should have won the game for City in normal time but Green smothered his low shot, then Gardner hit the post for the second time in the final moments before extra-time.
Gardner was not to be denied after 94 minutes as his swerving shot from 25 yards slipped through Green's grasp into the corner of the net. When West Ham's Kieron Dyer volleyed over from a good position, Birmingham were able to celebrate their return to Wembley.