Blues began their Carling Cup campaign what was ultimately narrow 2-1 victory over League 2 side Hereford United at St. Andrew's on Tuesday evening.
First half goals from Garry O'Connor and Gary McSheffrey sent Steve Bruce's side into what looked like being a convincing lead.
But Graham Turner's United side hit back with a 74th minute strike from Theo Robinson.
And had it not been for some heroic goalkeeping by Blues debutant keeper Richard Kingson, Blues may well have found themselves being taken into the lottery of extra time and possible penalties.
Steve Bruce made seven changes to side that had overcome Derby at the weekend.
T
he only four players remaining from Saturday's starting line-up at Pride Park were the defensive trio of Stephen Kelly, Stuart Parnaby and Liam Ridgewell and Gary McSheffrey in midfield.
Kelly lined up alongside Liam Ridgewell at the heart of the Blues defence, with Parnaby slotting in at right back.
Within seconds of the kick off Kingson was almost embarrassed when United's Theo Robinson charged his clearance down.
But fortunately for Kingson the ball rebounded straight back past the Blues keeper and out for a goal kick.
Blues went close to taking the lead after just three minutes when Neil Danns was brought down just outside the box.
Gary McSheffrey curled in the resultant free kick, which was deflected off the wall and onto the roof of the net for a corner.
Then on seven minutes some great attacking play saw Seb Larsson slip the ball to Rowan Vine on the left of the box.
Vine wrong footed his marker before unleashing a crisp shot which United keeper Wayne Brown did brilliantly to push away for a corner.
The first yellow card came after just 11 minutes when Robinson was booked for a crude challenge on Blues right back Parnaby.
Blues were spraying the ball around the pitch with ease, but failing to produce that final killer pass or shot.
That was until the 27th minute when Mat Sadler found himself free on the left of the visitors' box and curled in a perfect ball just beyond United's defence for Garry O'Connor to run in and volley the ball home from just six yards out.
Gary McSheffrey had an ideal opportunity to double Blues' lead on the half hour mark, but his close range angled effort was well held by Brown.
But on 37 minutes, McSheffrey did find himself on the scoresheet.
Rowan Vine threaded an inch perfect ball into the box from the right touchline and McSheffrey hit a fierce first time shot, which squirmed under Brown's body, despite his best efforts.
Minutes later Blues were given a scare when Toumani Diagouraga went on a surging 40 yard run towards the Blues box.
Just as he reached Kingson's area, Mat Sadler lost his footing and the ball fell to Clint Easton, but his crisp shot was well-saved by Kingson.
Half time: Blues 2 Hereford 0
United started the second half brightly and only a fine double save by Kingson - first with his hands from Robinson and then with his legs from Lionel Ainsworth prevented the visitors from reducing the deficit.
The second booking of the evening came just before the hour mark when Karl Broadhurst tripped Neil Danns on the edge of the box as he raced through towards the goal.
Seb Larsson flighted the free kick over wall, but Brown did well to catch the ball diving to his right.
Just after the hour mark United boss Graham Turner made a double substitution when Kris Taylor was brought on for Ben Smith and Steve Guinan was introduced in place of Trevor Benjamin.
The next chance of the game fell to the lively McSheffrey who seems to have rediscovered his form and he launched a tidy effort from the edge of the box which fizzed just past top corner of the visitors' goal.
Hereford were having the odd foray, but at this point in the match most of their attempts on goal were speculative long-range efforts.
But it was only a matter of time before their endeavour and hard work paid dividends.
Some sloppy play by Blues saw Mehdi Nafti dispossessed just inside his own half.
United broke down the right before Easton pulled the ball back for Robinson to smash the ball home from some eight yards.
In fairness on the balance of second half play alone, it was no less than Turner's side deserved.
Immediately after the goal Sone Aluko came on in place of Nafti.
United had an excellent chance to level the score on 78 minutes and would have done so had it not been for that man Kingson again.
Kingson saved Robinson's shot from 12 yards out with his body.
The ball rebounded to substitute Kris Taylor who looked certain to score from close range, but Kingson was equal to the task and threw his body in the way for yet another block.
The ball fell to Taylor on the right of the area and his angled effort went straight across the front of the Blues goal line, before bouncing off the goalpost and out for a throw in for Blues.
As the game came towards its conclusion, Hereford continued to hunt for an equaliser.
But with five minutes to go McSheffrey broke free and let loose with a fierce drive which flew just over.
In one of the final actions of the game, Neil Danns tried his luck with an acrobatic scissor kick, which was just off target.
At the end of the game Blues could count themselves fortunate that they weren't made to pay for their below-par second half performance and that they are successfully in the hat for the 3rd Round Carling Cup draw.
Full-time: Blues 2 Hereford United 1
Blues: Richard Kingson, Stuart Parnaby, Liam Ridgewell, Stephen Kelly, Mat Sadler, Sebastian Larsson, Mehdi Nafti (Sone Aluko), Neil Danns, Gary McSheffrey, Rowan Vine, Garry O'Connor.
Subs not used: Colin Doyle, Radhi Jaidi, Cameron Jerome, Mikael Forssell.
Goals: O'Connor 27, McSheffrey 38.
Bookings: none
Hereford: Wayne Brown, Trent McClenahan, Richard Rose, Karl Broadhurst, Lionel Ainsworth, Clint Easton, Ben Smith (Kris Taylor), Trevor Benjamin (Steve Guinan), Theo Robinson, Toumani Diagouraga, Dean Beckwith.
Subs not used: Mike Ingham, John McCombe, Simon Johnson.
Bookings: Robinson, Broadhurst.
Goals: Robinson 74.
Attendance: 10,185.
Referee: Martin Atkinson (W Yorkshire).
Attendance: 10,185




