The Bantams booked their place in the Bristol Street Motors Trophy Quarter-Finals with a 1-0 win over Sky Bet League One side Derby County at Pride Park.
Sam Stubbs netted midway through the second half from a Harry Chapman corner, as City saw out a late rally from the Rams to secure their spot in the area semi-finals for the first time since 2012/13.
On a chilly evening in Derbyshire, the visitors - having made seven changes from Saturday's Sky Bet League Two defeat at home to Crawley Town - started the stronger, as Bobby Pointon had two half-chances within the opening 10 minutes.
The City academy graduate found space between Derby’s lines before sending a shot over Josh Vickers crossbar, who later had to force clear a Chapman cross from under Pointon moments later.
Despite a few openings for the hosts - the most notable being a narrowly-wide Joe Ward free-kick - City went closest to edging in front just after the half-hour mark.
After some effective high pressing from Alex Gilliead, Chapman was played through inside Derby’s area, but his right-footed shot bounced off Sonny Bradley’s boot and behind for a corner.
Similarly to the first, the second half began with very little splitting the two sides.
Two of Derby’s second-half substitutes, Nathaniel Mendez-Laing and Conor Hourihane, combined on the hour mark, when the latter was found in space in the area before sending a thunderous shot goalwards - but the strike cannoned of the sliding Sam Stubbs.
As Alexander’s men grew back into the encounter, a succession of corners would eventually lead to the Bantams breaking the deadlock, through Stubbs.
Chapman’s set-piece was swung deep into the area and met by Stubbs, who rose highest to nod home his first goal of the season, edging the visitors in front.
As Derby scrambled for a way back into the game, the chances kept falling to the visitors.
Gilliead and Chapman had low, driven shots stopped by Vickers, while moments later, the ball fell almost perfectly for Kevin McDonald on the edge of the area, but the Scot sent a shot over into the empty North Stand.
Looking to go from goal provider to goalscorer, Chapman danced through the right side of Derby’s defence, but his delicate shot heading for the far corner was blocked, before Liam Ridehalgh’s follow-up was further denied by the home defence.
Paul Warne’s men battled for a leveller as clock ticked into its final 10 minutes, with Tyreece John-Jules, Joe Ward and Hourihane all seeing chances thwarted by a resolute City backline.
The visitors remained a threat, and almost doubled their advantage in stoppage time on the counter attack. While Derby committed bodies forward, Emmanuel Osadebe broke from a Rams corner and found Gilliead down the right flank.
He played second-half substitute Andy Cook into space in the area, but Josh Vickers was quickly off his line and able to snuff out the danger.
A valiant final half-hour showing from the Bantams meant they were able to successfuly repel Derby's advances and see out the victory.
City book their place in Friday's regionalised quarter-final draw, sending the 734-strong travelling faithful back to West Yorkshire in full voice.
DERBY: Josh Vickers, Kane Wilson (Tyreece John-Jules 67'), Sonny Bradley, Tom Barkhuizen, James Collins, Liam Thompson (Max Bird 46’), Louie Sibley (Nathaniel Mendez-Laing 46’), Callum Elder (Eiran Cashin 66’), Tyrese Fornah (Conor Hourihane 46’), Joe Ward, Curtis Nelson. Subs not used: Joe Wildsmith, Dajaune Brown.
CITY: Colin Doyle, Liam Ridehalgh, Ash Taylor, Richie Smallwood (C, booked 57’), Alex Gilliead, Sam Stubbs, Vadaine Oliver, (Andy Cook 82’) Harry Chapman (Clarke Oduor 82’), Bobby Pointon (Emmanuel Osadebe 82’), Kevin McDonald (Matty Platt 88'), Jonathan Tomkinson. Subs not used: Harry Lewis, Tyler Smith, Matt Derbyshire.
GOALS: Stubbs (66’).
ATTENDANCE: 3,831 (734 visiting supporters).