Richard Keogh got the ball rolling with a close-range header inside the opening 30 minutes, before Jake Buxton added a second from a similar position just four minutes later.
Theo Robinson looked to have blown away any sort of pre-season cobwebs, as he diverted Michael Jacobs’ clever flick four minutes later, to hand the Rams a three goal lead at half-time.
However, Alan Knill’s side refused to give up, and the Iron showed real fighting spirit with second-half goals from Andrew Barcham and Mike Grella either side of Buxton’s 53rd minute thumping header.
Bobby Grant helped set-up a grandstand finish after Robinson saw his 72nd minute spot-kick saved, but Nathan Tyson’s downward header seven minutes from time looked to have secured the victory.
However, two goals in the allotted five minutes of extra-time from substitute Connor Jennings and a penalty from Grant took the game to 120 minutes.
Neither side could find a way through in extra-time, so penalties ensued. Unfortunately for the Rams, Tom Naylor crashed the final penalty off the underside of the crossbar, as Scunthorpe booked their path into the Second Round of the competition.
In the opening 20 minutes the Rams bombarded the Scunthorpe defence, and were unfortunate not to find themselves a goal ahead as goalkeeper Sam Slocombe performed heroics in the visitor’s net.
With just two minutes gone on the clock, the returning Craig Bryson ghosted forward and threaded a neat ball through to Robinson on the edge of the Scunthorpe penalty area. The former Millwall striker opened up his body well, but curled his right-footed effort narrowly over the crossbar.
Moments later, in a congested penalty area, Tyson did well to poke the ball through to 17-year-old midfielder Will Hughes. The Academy graduate took a touch before smashing the ball towards goal, but ‘keeper Slocombe was equal to it, and tipped the ball over from point blank range.
The Rams continued show their attacking prowess on 15 minutes, as defender John Brayford’s deflected right-wing cross landed perfectly for Robinson, who used all his neck muscles to divert the ball goal-wards, however once again Slocombe produced a fine save to deny the Rams the opener.
However, Nigel Clough’s men did not have to wait much longer for their breakthrough, as three goals flowed in quick succession before the half-time interval.
With half-an-hour gone, Jacobs’ left-wing corner was met by the towering head of the Rams’ captain Keogh, whose effort snuck past ‘keeper Slocombe into the net as the former Coventry City defender marked his full Derby County debut with a goal.
Just four minutes later the Rams doubled their advantage. From another Jacobs set-piece, Buxton rose highest and nodded the ball into the smallest of gaps between Slocombe and his far post to give Clough’s side a two goal lead.
Before the half-time whistle was blown, Jacobs secured his third assist of the opening 45 minutes as the Rams raced into a three goal advantage. The summer signing from Northampton Town cleverly flicked Paul Coutts’ corner into the path of Robinson, who diverted the winger’s effort into the roof of the net.
In the second-half Alan Knill’s side started brightly, and with 52 minutes gone, Barcham ghosted past three Rams players before sliding the ball beyond the reach of ‘keeper Frank Fielding, into the net.
However, Clough’s men responded immediately, as just one minute later, Jacobs bent in another trademark free-kick midway inside the Scunthorpe half, and former Mansfield Town defender Buxton powerfully headed the ball past Slocombe to secure his double.
With 62 minutes gone, Clough introduced Ben Davies and Naylor in place of Bryson (groin) and Gareth Roberts (hamstring), as the duo stepped up their comeback to full fitness ahead of Saturday’s npower Championship opener against Sheffield Wednesday.
The Iron refused to give up as former Leeds United striker Mike Grella powered past two Rams defenders before sending a thunderbolt in off Fielding’s far post, to halve the visitor’s deficit.
With 18 minutes remaining, the Rams were handed a golden opportunity to put the game beyond doubt, as central defender Keogh went down in the penalty area under the challenge of former Watford man David Mirfin.
Robinson took responsibility, and the 23-year-old striker stepped up confidently, but saw his spot-kick superbly clawed away by Slocombe.
The away side broke away in a swift counter-attacking move, and Knill’s side set-up a nervy final quarter as Grant fired home Mark Duffy’s right-wing cross - the visitor’s goal coming just 24 seconds after Robinson’s missed penalty.
Tyson thought he had put the Rams’ mind’s at ease with his first ever competitive Derby County goal – a stooping header from summer-signing Coutts’ right-wing cross, but two goals in the five minutes of added time completed an unbelievable chain of events at Pride Park.
Jennings scrambled the ball home from almost on the goal-line after an excellent reflex stop from Fielding, before Grant coolly fired his 95th minute penalty past the former Blackburn Rovers ‘keeper to send the away supporters into euphoria.
In the opening period of extra-time, Grant spurned the best chance of the half after he held off the advances of Keogh before firing agonisingly wide of goal from a tight angle.
In the second 15 minutes, Mason Bennett and Robinson both came within inches of sealing the victory, but somehow the ball managed to evade the duo on two separate opportunities after good work from Jacobs and Tyson respectively.
A further three opportunities fell the Rams’ way, as Jacobs, Coutts and Davies all went close, before referee Dean Mohareb blew the final whistle and sent the game into penalties.
Grella and Davies missed both teams’ opening spot-kicks, before Callum Kennedy, Nathan Tyson and Josh Walker dispatched their respective penalties to make it 1-2 to the away side.
John Brayford saw his penalty expertly saved by Slocombe, then Duffy watched on as his fiercely struck effort cannoned off the inside of the post.
Keogh, Grant, Robinson, Tom Newey, Jacobs, Jimmy Ryan, Mirfin, Buxton and Jennings were all successful from the spot, before Naylor stepped up and crashed his penalty against the underside of the crossbar as the Rams missed out on a place in the Second Round of the competition.
Derby County: Fielding (GK); Brayford, Keogh, Buxton, Roberts (Naylor 62); Coutts, Hughes (Bennett 87), Bryson (B. Davies 62), Jacobs; Tyson, Robinson.
Subs Not Used: Legzdins (GK), Lelan, Doyle, S. Davies.
Scunthorpe United: Slocombe (GK); Kennedy, Ribeiro, Mirfin, Newey; Duffy, Walker, Ryan, Grant; Barcham (Jennings 84), Grella.
Sub Not Used: Severn (GK), Gibbins, Godden, Hughes, Howe, Keegan.
Attendance: 4,724 (Including 364 Visiting Supporters)