Birmingham opened up a five-point lead at the top of the Coca-Cola Championship after thrashing rock-bottom Southend 4-0 at Roots Hall.
The Shrimpers came crashing down to earth after taking Tottenham to extra-time in their midweek Carling Cup quarter-final, with DJ Campbell giving Blues an eighth-minute lead.
Stephen Clemence made it 2-0 before Gary McSheffrey's brilliant free-kick and a late fourth from Radhi Jaidi completed the rout.
David Nugent scored the only goal of the game as Preston leapfrogged Derby into second place with a hard-fought 1-0 win over surprise package Colchester.
The Rams dropped to third after being held to a goalless draw at play-off chasing Burnley.
An extraordinary injury-time equaliser from goalkeeper Mark Crossley rescued a 3-3 draw for Sheffield Wednesday against in-form Southampton.
The veteran stopper headed home a corner after Saints had led 2-0 and 3-1 thanks to goals from Grzegorz Rasiak, Kenwyne Jones and Bradley Wright-Phillips.
Glenn Whelan was Wednesday's other hero, with his brace twice cutting the deficit.
Stoke took advantage of Southampton's slip-up to move fourth, Liam Lawrence's 71st-minute winner proving enough to beat Ipswich at Portman Road.
A new era at Cardiff failed to spark a change of fortune as Dave Jones' men were held to a goalless draw at Leicester.
The long-time leaders are now seven games without a win and will hope the completion of a protracted takeover of the club eventually stops the rot.
West Brom striker Kevin Phillips scored twice in first-half stoppage-time to rescue a 2-2 draw at Plymouth, who had led through goals from Barry Hayles and Lilian Nalis.
The Baggies also had Neil Clement sent off in the closing seconds.
Wolves needed a last-gasp Jody Craddock leveller to take a point at home to Norwich.
The second of Robert Earnshaw's two goals looked to have won it for the visitors after Karl Henry had cancelled out his 11th-minute opener.
Martin Rowlands gave QPR a much-needed 1-0 win in their basement battle with fellow strugglers Barnsley.
Luton continued their recent resurgence with a 3-1 win over Coventry.
Ahmet Brkovic put them ahead but then scored at the wrong end to draw the visitors level.
But Rowan Vine and a brilliant free-kick from Dean Morgan got him out of jail.
In the early kick-off, Leeds failed to make home advantage pay as relegation rivals Hull ground out a potentially priceless point at Elland Road.
There were precious few genuine goalscoring opportunities in a feisty Yorkshire derby which left both clubs deep in relegation trouble.