Ross McCormack's penalty on the stroke of half-time and Peter Whittingham's superb second-half free-kick saw the Bluebirds squeeze into Round Three despite the Dons giving them a fright late-on.

Substitute Sean O'Hanlon's 74th-minute header threatened to spark a comeback from Roberto Di Matteo's men, but their Carling Cup run would ultimately end at Ninian Park.

It was a spirited performance from Di Matteo's charges - an almost entirely different team from the one that swept Huddersfield aside at the weekend but one no less determined to fight for the cause.

Six changes to the starting eleven meant there would inevitably be some points to prove, along with valuable match time to gain.

Among those in the latter category was midfielder Paul Mitchell, playing his first competitive game since shattering his leg nearly 19 months ago, and 16-year-old Adam Chicksen - both of whom played 90 minutes against the FA Cup finalists.

While Mitchell will be the first to admit he's not yet back to his swashbuckling best, there were promising flashes of the midfielder of old on a night many thought the 26-year-old would never see after that horrible afternoon in Nottingham nearly two years ago.

Craig Dobson holds the ball up on his first start of the season.

One moment in particular brought a cheer from the hundred or so travelling supporters - Cardiff's Joe Ledley feeling the full force of the Mancunian on 63 minutes, having been given what can only be described as a hospital ball from team mate Miguel Comminges.

It shook Ledley to the core and Mitchell from a mid-game slumber as he finished the match with a genuine second wind.

Mitchell aside there was another excellent display from Chelsea loanee Shaun Cummings in defence, a lively outing from Jemal Johnson down the right and another learning experience for young Sam Baldock in attack.

Despite looking dangerous in possession in the opening stages, Cardiff suffered an awful start to the game when they lost both full-backs to injury in the first 20 minutes.

Tony Capaldi went first, replaced by Comminges after just 11 minutes, before Darcy Blake followed him down the tunnel, replaced by Paul Parry nine minutes later.

McCormack was their liveliest outlet, making good ground down the right on 21 minutes after a slip from Jude Stirling. Had Cummings not been so quick out of the traps to prevent Parry controlling the cross it might have come to more.

Sam Baldock in action for the Dons at Cardiff City.

Whittingham drilled a 25-yard shot just past the post shortly afterwards while the Dons were living on relative scraps. Baldock found space to run at the defence 32 minutes before seeing his effort charged down by the imposing Darren Purse.

Given the kind of reception reserved for former Swansea players visiting the home of their bitter rivals, Willy Gueret wasn't a popular man at Ninian Park.

He did little to endear himself to the home support with a terrific save from debutant Eddie Johnson - clawing the American's shot onto the bar on 41 minutes - but from the resulting corner came Cardiff's breakthrough.

Whittingham's delivery from the right caused a real scramble in Dons territory and eventually saw Scimeca felled under Diallo's challenge.

It took a full four minutes for Scimeca to be stretchered off but, once his safe passage off the pitch had been negotiated, McCormack made no mistake with the spot-kick.

Johnson whistled a shot across the Cardiff goal in response before the break but the Dons' chances of reaching the break with parity were gone.

Whittingham fired a warning shot as to his set-piece abilities just after half-time, curling just past Gueret's right-hand post within five minutes, but he found his range on 58.

Alan Navarro puts Paul Parry under pressure.

Capitalising on Stirling's foul on McCormack just right of centre, the former Aston Villa winger whipped the ball over the wall and into the corner with sumptuous ease.

But this Dons group is not one to throw the towel in and set about finding an avenue back into the game, led frequently by Jemal Johnson.

They were rewarded on 76 minutes, though there was an element of fortune about the goal. Mitchell's free-kick from deep was met firmly by O'Hanlon in the penalty area but there was definitely a hint of a slip from Heaton as the ball flew past him.

McCormack nearly regained the two-goal advantage immediately but saw his instinctive effort come back off the post at the other end, and as the Dons chased an equaliser, chances continued to appear.

The best probably fell to Eddie Johnson, who turned Ledley's cross criminally wide with six minutes to play.

Cardiff City (4-4-2): Heaton; Blake (Parry 20), Purse, R. Johnson, Capaldi (Comminges 11); Whittingham, Scimeca (Morris 45), McPhail, Ledley; E. Johnson, McCormack.

Subs not used: Enckelman, Bothroyd, Dennehy, Thompson.

Goals: McCormack (45+3 pen), Whittingham (58)

MK Dons (4-4-2): Gueret; Cummings, Diallo, Stirling (O'Hanlon 66), Lewington (c) (King 66); J. Johnson, Mitchell, Navarro, Chicksen; Dobson, Baldock.

Subs not used: Abbey, Wright, Regan, Leven, Belson.

Goals: O'Hanlon (74)

Referee: Rob Shoebridge (Derbyshire)

Attendance: 6,334