A headed double from James Hanson on his 300th appearance in City colours, plus efforts from Kyel Reid and substitute Steven Davies, secured a sensational away victory for Phil Parkinson's men at Peterborough United.
Partnering Wes Thomas in attack, Hanson gave City a deserved lead on the stroke of half time when he planted a header past a rooted Ben Alnwick following a cross into the box from a rejuvenated Reid.
City needed an important goal-line clearance from Stephen Darby straight after the break to preserve their lead - the Bantams skipper producing a superb block to deny Jon Taylor from close range - before Parkinson's side went on the attack once again.
Reid doubled the Bantams' advantage roughly ten minutes into the second period after engineering himself a shooting opportunity and firing low past Alnwick following Lee Evans' long throw-into the box.
Hanson put City even further in front midway through the half when he rose to meet James Meredith's cross into the box before glancing home a header in off the far post.
Sub Davies then put the icing on the cake for the Bantams thirteen minutes from time when he converted from close range after Tony McMahon had driven Meredith's flighted centre back across goal.
FT: Peterborough United 0 Bradford City 4
90+1min: SUB - The Bantams bring on Jamie Proctor for Hanson.
90min: There will be three minutes of time added on at the end of the game.
90min: Nabi's free-kick from just outside the box is superbly tipped around the post thanks to a brilliant diving save from Williams.
88min: Angol's ball across the box finds Coulthirst lurking but Burke does just enough to prevent the striker from getting a shot in just in front of the six yard box before Meredith can kick clear.
87min: Nabi's corner delivery whistles across goal and out for a goal kick as Williams tries to punch clear.
84min: SUB - The Bantams bring on Mark Marshall for Reid.
82min: Nabi's teasing delivery into the box from a wide free-kick floats just wide of Williams' far post.
77min: GOAL!!!!!!!!!!!!!!!!!! Peterborough United 0 Bradford City 4 - The Bantams have a fourth! Meredith's searching cross finds McMahon lurking over by the far side of the penalty area. McMahon strikes across goal and Davies converts from close range.
74min: Angol's effort from just outside the box sails high over Williams' bar.
74min: Reid's cross into the box tries to find Davies but the effort is headed clear. A lurking Evans is waiting just outside the box for the loose ball but his low effort rolls wide of Alnwick's near post.
73min: SUB - The Bantams bring on Steven Davies for Thomas.
71min: SUB - Peterborough bring on Lee Angol for Zakuani.
68min: GOAL!!!!!!!!!!!!! Peterborough United 0 Bradford City 3 - Hanson heads City even further into the lead with another headed goal! Meredith's clipped cross towards the far post perfectly picks out the run of Hanson and the striker glances in a header off the far post.
64min: YELLOW CARD - Zakuani is booked for a late tackle on Darby over by City's right flank.
63min: YELLOW CARD - Baldwin is booked for catching McArdle with an aerial challenge as City look to clear the ball from inside their own box.
60min: Thomas' neat turn outside the area gives him the time and space to find McMahon inside the box with a forward pass. McMahon's cut-back from the byline picks out Evans but the Welshman's low first time effort from around the edge of the box hits the outside of Alnwick's near post.
59min: Taylor's run and pass in-field finds Smith but his strike from distance is straight at Williams.
56min: GOAL!!!!!!!!!!!!!!!!!!!!!!!!!!! Peterborough United 0 Bradford City 2 - Reid doubles City's advantage! Evans' long throw-in into the box eventually drops into the path of Reid and the winger twist and turns into a shooting position before firing a low left-footed drive past Alnwick and into the far bottom corner.
54min: Baldwin's first time cross from near the corner flag drops invitingly into the path of Michael Smith but the Peterborough player fires over with an effort on the half-volley from just inside the box.
52min: After being off the pitch for a couple of minutes changing his boots, leaving City temporarily down to ten men, Hanson is eventually allowed back onto the pitch by the match officials.
46min: What a block from Stephen Darby! With the ball deep inside City's area following Couthirst's teasing ball, Nabi sees his shot from close range well saved by Williams before the rebound drops into the path of Jon Taylor. With Williams out of position following his save from Nabi, Taylor looks set to drill home but Darby flings himself at the ball and somehow blocks the effort on the goal line. Maddison fires in a teasing cross a few seconds later but
46min: The Bantams restart the second half.
HT SUB - Peterborough make their second sub of the afternoon ahead of the second period, bringing on Chris Forrester for Martin Samuelsen.
HT: Peterborough United 0 Bradford City 1
45min: There will be one minute of time added on at the end of the first half.
45min: GOAL!!!!!!!!!!!!!!! Peterborough United 0 Bradford City 1 - Hanson heads the Bantams into the lead on his 300th appearance in City colours! Hanson is first to Reid's cross into the box and the striker heads past a rooted Alnwick as the ball nestles in the net just inside the near post.
40min: Thomas' shot from the edge of the box has the sting taken out of it via a deflection off Baldwin before Alnwick gathers up the loose ball ahead of McMahon.
39min: Meredith's deflected cross drops into the path of Thomas inside the box but the striker's effort while under pressure from a couple of Peterborough defenders drops wide of Alnwick's near post.
37min: Reid's searching cross is headed down into the mix by McMahon towards the waiting Lee Evans but the Welshman can't quite get over the ball properly and his half-volley on the turn from around twelve yards out.
34min: SUB - Peterborough bring on Marcus Maddison for Andrew Fox.
32min: James Meredith's forward pass finds Wes Thomas in space inside the area. Thomas fires the ball across the six yard box, trying to find Hanson for a simple tap-in, but Jack Baldwin is well-positioned to put behind for a corner.
30min: Adil Nabi goes for a goal with a free-kick from outside the box but his curling effort is straight into the arms of Williams.
26min: Nichols' left-footed curler from just outside the area flies wide of Williams' far post.
24min: Kyel Reid gets the better of Michael Smith over on City's left flank before fizzing in a teasing cross that Gabriel Zakuani can't really touch for fearing of the ball hitting off him for a potential own goal. The cross instead ends up in the arms of the diving Alnwick, but only at the second attempt after initially fumbling with Hanson waiting to pounce.
20min: McMahon's corner delivery bounces into the path of Reece Burke, who fires a cushioned half-volley into the ground before Alnwick pushes the effort away from right in front of goal with McArdle lurking nearby.
6min: Tom Nichols sends a looping half-volley from just outside the box sailing over Ben Williams' bar.
5min: Rory McArdle sends a downward header wide of Ben Alnwick's far post following Tony McMahon free-kick delivery into the box from a wide position.
0min: Peterborough kick off the match.
PETERBOROUGH UNITED LINE UP:
Alnwick, Smith, Baldwin, Zakuani, Fox, Bostwick, Samuelson, Taylor, Nabi, Nichols, Coulthirst
Subs: Henry, Oztumer, Maddison, Santos, Angol, Forrester, Toffolo
Peterborough United substitutions:
Maddison for Fox (34), Forrester for Samuelsen (46), Angol for Zakuani (71)
Peterborough United cautions:
Baldwin (63), Zakuani (64)
BRADFORD CITY LINE UP:
Williams, Darby, McArdle, Burke, Meredith, McMahon, Evans, Cullen, Reid, Thomas, Hanson
Subs: Cracknell, N Clarke, Marshall, Knott, Morris, Proctor, Davies
Bradford City substitutions:
Davies for Thomas (73), Marshall for Reid (84), Proctor for Hanson (90+1)
Referee: D Whitestone
Assistant Referee: M Mellor
Assistant Referee: R Atkin
Fourth Official: N Cooper