Millwall's survival hopes were dealt a devastating blow as fellow strugglers Birmingham City edged to victory by the odd goal in five to send The Lions spiralling to the foot of the Championship table.
Boss Ian Holloway had billed this as a 'must not lose' match and his team selection was certainly bold, starting with a 3-4-1-2 formation with Alan Dunne, Paul Robinson and Shane Lowry at the back and Scott McDonald operating just behind Steve Morison and DJ Campbell up front.
Morison went close on 10 minutes when he found space in the penalty area, and saw two shots in quick succession clawed away by Blues keeper Darren Randolph.
The striker really should have done better six minutes later when he had time and space to pick his spot from 12 yards, but lifted his effort over the bar.
Lee Clarke's Blues took the lead against the run of play on 18 minutes when the home side failed to clear Paul Caddis's cross and midfielder Jordan Ibe's low drive flew into the bottom corner.
That lead lasted just 12 minutes and The Lions grabbed a deserved leveller when Morison muscled his way into the area and hit an angled drive that flew into the net off Blues skipper Paul Robinson from four yards.
Having worked so hard to get back on level terms, Millwall found themselves behind barely four minutes later when their defence were caught napping enabling Andy Shinnie to head home the simplest of goals from Tyler Blackett’s delivery.
Lions boss Holloway reverted to a flat back four at this stage, with Dunne switching to left-back and Fredericks dropping into the right-back berth.
Owen Garvan, who worked tirelessly throughout, was unfortunate to see a free-kick fly narrowly wide moments before the break as The Lions went in trailing by the odd goal, but still very much in the game.
Holloway made a double change at the start of the second-half with Dunne and Lowry making way for Simeon Jackson and Mark Beevers.
There were howls of disbelief when visiting skipper Robinson clearly handled Campbell's cross three minutes after the restart, but he was so close to the home striker that referee Scott Mathieson ruled he couldn’t have got out of the way and instead awarded a corner.
It proved to be a crucial decision and three minutes later the home defence was sliced open when Chris Burke sprinted past Martyn Woolford and delivered a perfect cross for Zigic to head home from six yards.
Millwall tried to raise a head of steam with Garvan firing narrowly wide and then Abdou blasting over the bar from inside the area.
Boss Holloway made his third and final change just after the hour mark when he introduced Stefan Maierhofer for Campbell and the giant Austrian headed past the post moments later from a deep Garvan free-kick.
Woolford perhaps took a touch too many in a good central position and fired off target from 16 yards, Jackson was denied by Randolph at point-blank range and when Maierhofer whipped the ball back in, Garvan glanced a header just wide as The Lions kept plugging away trying to reduce the deficit.
They were handed a lifeline three minutes from time when Jackson was fouled in the box, and promptly swept home the resulting spot-kick straight down the middle.
However the four minutes of injury-time saw Blues hold on to their precious one goal advantage with Millwall's only real goal threat right at the death when Beevers headed straight at Randolph from Garvan’s free-kick.
Forde, Dunne (Jackson, 46mins), Robinson, Lowry (Beevers, 46mins), Fredericks, Abdou, Garvan, Woolford, McDonald, Morison, Campbell (Maierhofer, 61mins). Subs not used: Bywater, Bessone, Upson, Onyedinma.
Fredericks, Robinson, Abdou (59mins), Garvan, McDonald (70mins), Garvan (73mins), Fredericks (76mins), Robinson (84mins)
Robinson (30mins, og), Jackson (88mins, pen)
Birmingham City: Randolph, Robinson, Martin, Burke, Ibe (Gerguson, 85mins), Zigic, Reilly, Shinnie, Spector, Caddis, Blackett. Subs not used: Doyle, Macheda, Lee, Rusnak, Brown, Lovenkrands.
Bookings: Reilly (44mins), Zigic (53mins), Ferguson (90+1min)
Scorers: Ibe (18mins), Shinnie (35mins), Zigic (51mins)
Ref: S. Mathieson
Att: 9,268 (away 635)