The home side opening the scoring in a poor opening period for the Blues when Reuben Reid netted from the penalty spot in the 23rd minute following a Liam Noble foul on Dean Furman. Carlisle though improving markedly after the break to equalise through a Jon-Paul McGovern free-kick on 57 minutes. No further goals though up to the end of extra-time seeing the tie go to penalties, in which Matty Robson for United and Chris Taylor and Josh Parker had their spot-kicks saved, that meaning that the Blues went through on the back of a 4-2 success.
The Latics started brightly and early on Matt Smith headed wide from a corner before Chris Taylor wastefully volleyed a Filipe Morais cross over the top from close range, with Reid then having a 25-yard shot easily saved by Adam Collin after 14 minutes. Eight minutes later and Zander Diamond had an effort from the middle of the United box well blocked by Danny Livesey before the Latics did indeed take the lead with 24 minutes on the clock, Noble bringing down Furman for a penalty, with Reuben Reid then stepping up to hit the spot-kick powerfully just beyond the reach of Collin.
After a particularly quiet spell in the game, Furman went into the home side of the referee's notebook for a foul on Francois Zoko, with Furman then involved for the right reasons as we ticked into injury time when he kneed Kieran Lee's cross inches wide of Collin's left-hand post. Carlisle themselves then coming close to grabbing a goal before the break when first Noble headed a Tom Taiwo cross narrowly wide then a Zoko pass once more found Noble, this time for a 20-yard drive straight into the gloves of Alex Cisak.
The first action of the second-half saw Andy Welsh come on for Noble with the Blues changing to a 4-4-2 formation, that seeing the Blues pick up the pace as they found an equaliser from a set-piece in the 57th minute. Diamond bringing down Craig Curran for a foul 25 yards out, which McGovern delightfully curled over the Latics defensive wall and into the top corner of Cisak's net. United then almost making it 2-0 two minutes later when Curran flicked a Robson cross narrowly wide of the target from close range.
Taylor then became the second home player booked on 66 minutes for a foul on Robson, with an on-top Carlisle then twice going close in the 76th minute when a low ball in from James Berrett was almost bundled in by Curran until Lee was able to clear off the line. Robson then picking up on the loose ball with a well-hit shot that was pushed away by Cisak, with Diamond then finally hacking away from the danger area. Eight minutes from time and for the home side Matt Smith then heading a Taylor cross bang onto the face of Collin's crossbar from close range.
Then as the game began to get end-to-end Zoko had a shot easily stopped by Cisak before Josh Parker's pacey long-range effort was held by Collin at the second attempt. Taiwo then made a good run forward for the Blues after 88 minutes when his low drive in had Cisak beaten only to ping away off the outside of the Oldham woodwork. The last chance of the game in normal time coming the way of the Latics when, in a move which saw Berrett booked as the referee waved advantage, Parker ran on before shooting well wide of Collin's goal from 20 yards out.
Taiwo was then the next United player yellow carded in the 93rd minute for a foul on Reid, from which Furman curled the free-kick in and former Blues trialist Jean-Yves M'voto headed weakly wide from close range. Up at the other end Carlisle substitute Rory Loy had a left-footed drive on the turn very well saved by Cisak. Smith then hitting the crossbar with a header again for the Latics in the 99th minute when he connected well with another Furman corner.
Shortly afterwards, and after a Livesey booking for dissent, it was Smith once more getting involved only to slice a Parker cross miles over the top. Then in the last action of the first-half of extra-time Zoko set up Taiwo for a 20-yard drive that was well pushed behind by Cisak, with Cisak then punching the resultant Berrett corner straight out to McGovern on the edge of the box, only for the former MK Dons midfielder to send an attempted volley high over the Oldham crossbar on the stretch.
Both sides started to huff and puff a bit in the final 15 minutes as penalties began to look inevitable, although Cisak was grateful in the 115th minute when McGovern's shot from the edge of the box deflected off David Mellor but straight into the home goalkeeper's gloves. Oldham though coming the closest to finding a late winner two minutes before time when Parker curled a 25-yard effort inches over the top, the Latics fans and players certainly wishing that had gone in 15 minutes later when United held sway 4-2 on spot-kicks.