It was far from the ideal introduction to the competition for Blues boss Alex McLeish, but the Terriers’ all-action display was a textbook example of the kind of upset for which the cup is famed.

The afternoon started well for the hosts when Luke Beckett prodded home from close range and although Garry O’Connor drew the Barclays Premier League side level before the break, the impressive Brandon volleyed home emphatically to seal the win.

The Terriers handed James Berrett a debut in midfield and the youngster had a satisfying first touch, dispossessing Fabrice Muamba in the centre circle with a well-timed challenge.

Then, after just three minutes, the hosts were ahead.

Danny Schofield took possession in a deep-lying position but was not tackled as he strode into Birmingham territory.

He made light work of Radhi Jaidi’s attempted block and after a quick give-and-go in the penalty area, he unleashed a shot at Maik Taylor.

Taylor spilled the scuffed effort but Beckett was first to the loose ball and he stabbed home into an empty net to kickstart the home crowd.

After 13 minutes, Town goalkeeper Matt Glennon was on hand to save Mikael Forssell’s low drive at the near post.

Brandon, meanwhile, was causing problems at the other end and twice earned corners by attacking the static City defence.

But a quick break following a corner drew the visitors level in the 20th minute.

Taylor set Daniel de Ridder free down the left and he played in Fabrice Muamba, who shrugged off Robbie Williams’ attentions to make room for a shot.

Glennon got a firm hand to it but when the ball broke it found O’Connor, who slotted home with ease.

The equaliser steadied Birmingham and only a linesman’s flag stopped them taking the lead after 24 minutes.

De Ridder was again the architect, breaking at pace and curling a cross high into the Huddersfield penalty box.

The ball took a deflection on its way to O’Connor who poked his shot past Glennon on the volley before seeing his celebrations cut short by an offside verdict.

The match remained open and the home team continued to play their part, Beckett and Malvin Kamara combining to give McLeish’s side another scare after half an hour.

Franck Queudrue was booked for a messy-looking lunge at Kamara and when the lively Brandon climbed highest from the resulting free-kick, he was unfortunate to be denied by a combination of Taylor and the woodwork.

Immediately after the restart, a hopeful punt up field landed at the feet of O’Connor 20 yards out but he could not force a meaningful save from Glennon.

Joe Skarz, a half-time substitute, presented Town with their first chance of the second half, fizzing a cross in from the left and finding the unlikely figure of Andy Holdsworth in the six-yard box.

But the skipper made a hash of the finish as the goal beckoned.

Birmingham then took the initiative, Gary McSheffrey and O’Connor both having passable shots.

McLeish took the opportunity to build on his side’s momentum by introducing Cameron Jerome – who played for the Terriers as as schoolboy but whose relationship with the club has soured since – in place of Forssell.

Predictably, the striker was treated to a chorus of boos.

The former Cardiff man immediately offered a different threat, harrying the defence with pace and brawn, but the crowd delighted in an overhit first touch which sent the ball skidding out of play.

McSheffrey, not impressing on Birmingham’s left despite plenty of possession, was gifted the ball on several occasions in the closing stages but produced little of note.

Jerome also fluffed his lines again, rolling the ball into touch when attempting a simple pass.

Instead it was Brandon who was left to claim the winner.

Beckett, clearly tiring but charging manfully down the wing, heaved a cross deep into the danger area.

As Liam Ridgewell and Jaidi were pulled to the near post, Brandon was given space at the opposite upright to drill home his volley.