Cody McDonald's 64th-minute winner extended the Bantams' run to six games without a win and hauled in the leaders, who were surprisingly held to a goalless draw at struggling Barnet.
Billy Kee scored twice as Burton jumped into the third automatic promotion place with a 2-0 win over Rotherham, who ended the game with nine men.
Kee opened the scoring on 36 minutes before the Millers had David Noble sent off in first half injury time for a bad foul on Jacques Maghoma.
Kee extended the home side's lead 10 minutes into the second half and Rotherham's fate was sealed when they also saw Michael O'Connor dismissed late on.
Cheltenham slipped out of the automatic promotion positions after a surprise 1-0 defeat at Dagenham & Redbridge, for whom Luke Howell scored the only goal of the game in the 58th minute.
Fourth-placed Exeter continue to look like real contenders after an impressive 3-0 win at Morecambe, veteran Jamie Cureton scoring twice and Arron Davies also getting on the scoresheet.
Northampton also moved into contention with a 3-1 win over Rochdale at Sixfields.
Clive Platt's 32nd minute header was cancelled out by Jason Kennedy for the visitors, before Kelvin Langmead and an Adebayo Akinfenwa penalty sealed the points for the home side.
A late equaliser from Kevan Hurst helped 10-man Southend hang on to the final play-off place in a 1-1 draw at Accrington.
James Gray put the home side in front in the 58th minute and despite Ryan Cresswell's 65th minute sending-off, the Shrimpers struck back through Hurst's equaliser four minutes from time.
Wimbledon remain rooted to the foot of the table after sliding to a 2-0 defeat at Chesterfield, whose second half goals came from Armand Gnanduillet and Jack Lester.
And Aldershot slipped back in the drop zone after a 2-1 home defeat to fellow strugglers Plymouth, for whom two goals from Jason Banton sandwiched an equaliser from Peter Vincenti.
Bristol Rovers eased their relegation fears with an impressive 2-0 win at Oxford, Lee Brown's 55th minute penalty setting them on their way and substitute Eliot Richards adding a second in injury time.
Wycombe's recent revival continued with a 4-0 hammering of York, two first half penalties from Dean Morgan setting them on their way before Joel Grant and Dave Winfield completed victory.
Fleetwood remain within reach of a play-off place after Jon Parkin's 26th minute header proved enough to give them a 1-0 win over Torquay at Plainmoor.