Blues claimed a vital three points on a dramatic night against Millwall at The Den.
First-half goals from Jordon Ibe and Andy Shinnie sandwiched in a Paul Robinson own-goal, before Nikola Zigic edged Blues further head shortly after the break. Millwall substitute Simeon Jackson's 88th minute penalty set up a tense finish to an enthralling encounter in South East London.
The turn of events - and goals - continued a familiar pattern of match-ups between the Lions and Blues on this patch in recent years; 6-0 in January 2012 and 3-3 last season.
Right from the off, this looked set to be an open affair as Ian Holloway named an attacking Millwall line-up.
Blues took the lead against the run of play with Ibe scoring the first goal of his loan spell from Liverpool in the 18th minute. Paul Caddis' cross from the right was only half-cleared, Chris Burke charged the ball down and it fell kindly for the teenager to fire a low effort into the bottom right corner off the outstretched palm of David Forde.
Millwall hit back on the half-an-hour mark. Steve Morison got in down the left past Caddis and drilled a shot across the face of goal that went in off the face of Robinson for an unfortunate own goal.
However, Lee Clark's battlers were back in front within the space of four minutes. Tyler Blackett's precise delivery from the left found Shinnie peeling off his marker from six yards to power home a header.
Blues were braced for a Millwall fightback after the break but the visitors dampened their hosts' hopes within seven minutes. From a counter-attack, Shinnie picked out the run of Burke down the right and his perfectly-weighted cross picked out the unmistakable presence of Zigic to thunder home a header beyond the hapless Forde in front of the 635 travelling fans.
The end-to-end nature of this fixture continued and Millwall threatened on several occasions. Jimmy Abdou skied an effort from inside the Blues box in the 57th minute, Jackson was denied by a superb sliding challenge from Aaron Martin in the 63rd minute and fellow Millwall sub Stefan Maierhofer nodded into the side netting from Owen Garvan's right-sided free-kick.
Canada international Jackson continued to be a menace for Millwall and, having been denied by a quick-thinking Darren Randolph charge in the 83rd minute, won the visitors a debatable penalty two minutes from the end. Martin was judged to have brought down Jackson, who stepped up to beat Randolph with a cheeky effort straight down the middle.
It set up a nail-biting finish - and one that Blues managed to survive for another memorable away day victory.