Crystal Palace and Leicester City suffered defeats and Watford also dropped points on a bad Friday for the promotion hopefuls, while Bristol City slipped into deeper trouble at the foot of the table.
Birmingham City produced a superb performance away from home to dent Crystal Palace's chances of going up with a 4-0 victory at Selhurst Park. Nathan Redmond, Ravel Morrison and Shane Ferguson did the damage for the visitors, while there was also an own goal for Damien Delaney on a miserable day for the fourth-placed Eagles.
Watford missed the chance to go second after being held to a thrilling 3-3 draw by Burnley at Vicarage Road. It had looked as though former Watford manager Sean Dyche would suffer defeat on his return to the club with Burnley, but Sam Vokes grabbed a last-gasp equaliser.
Leicester had to battle through virtually all of their game against Millwall with ten men after the dismissal of Wes Morgan in the third minute, but they could not quite hang on as Alan Dunne fired home a late strike to make the final score 1-0 and leave Nigel Pearson's men hanging on to a play-off spot ahead of the rest of the weekend's action.
Derby County increased the pressure on bottom club Bristol City as goals from Jeff Hendrick, Jamie Ward and Ben Davies sealed a 2-0 home triumph.
Blackburn Rovers began life without manager Michael Appleton by holding Blackpool to a 1-1 draw as Jordan Rhodes' header cancelled out Gary MacKenzie's opener.