United came up against Preston North End for the second time in this season's Central League Cup with the northern are semi-final to contest just along the road from Deepdale.
The hosts had finished top of Group B, having beaten United and Fleetwood and drawn with Morecambe, with the Blues beating Fleetwood and the Shrimps in their other two outings.
It was a keenly contested encounter with chances hard to come by through the opening stages.
United went closest to causing a moment when Gordon floated a lovely ball beyond the back line. Bell chased it but Pradic raced off his line to clear.
Preston showed when Coulton overlapped to meet a through ball from former United loanee Ethan Walker. The left back delivered but the shot was smothered as Walker stretched to meet it.
Stopper Gabe Breeze was called into action on 22 minutes when O'Neill and Seary worked their way into the area. A stinging bullet from the latter was going in but the keeper spread himself to get his legs in the way.
Carlisle started to enjoy some possession and a slip from Amaral presented Hardy with an unexpected opening midway through the half. He kept his head over it as he volleyed but Pradic threw arms up to divert it over the bar.
Half chances came and went for both teams, but it was United who thought they'd done enough when Harvey Gordon sparked an attack with a run and pass out of defence.
Bell touched it on for Bollado, and his strength took him past a strong challenge. He unleashed a thunderbolt but it rattled the inside of the post and bounced away to safety.
The hosts were immediately on the break and they went ahead as Walker slowed things down before bringing Coulton into play. His initial delivery was dealt with, but O'Neill was on hand to sweep it into the bottom corner.
United were stung and Fishburn forced a diving save out of Pradic just before the break when he bundled his way into the box. Bollado snaffled up the rebound but it was straight at the alert glovesman.
It was a scrappy start to the second period, with an overhead kick from Walker from the edge of the area the highlight of a tense spell.
Bollado was a willing runner but he was disappointed when he dropped a shoulder only to pick out Pradic's hands once again.
The blue shirts saw plenty of the ball without managing to carve much out, but they got the equaliser their efforts deserved when Lewis Bell skipped past two to go to a tight angle. His cross took at least one deflection and Pradic could do nothing as it spooned over his shoulder and over the line.
It felt as if the visitors were about to push on, but there was a real slap in the face when a ball from Seary fizzed across the face of goal. Taylor and Coulton went after it, and the referee had no hesitation at pointing to the spot when the pair tumbled to the floor.
Mikey O'Neill netted his second of the day with a neat spot kick finish.
Carlisle threw everything forward but their frustration was summed up in time added on when when Max Kilsby launched himself at a teasing cross from Taylor. His header had power, but Pradic got just enough on it to keep it out.
Preston North End - O'Neill (37, 82 pen)
Carlisle United - OG (79)
Carlisle United - Watt (87)
Preston North End - Pradic, K Taylor (Wallbank 68), Coulton, Amaral, Nevin (c), Blanchard, Seary, O'Neill, Rodwell-Grant (Hollan-Wilkinson 38), Bennett, Walker (Mawene 78). Subs - Lombard, Slater.
Carlisle United - Breeze, Gordon, Carr, Ellis, Kilsby, Nugent, Watt, L Bell, Bollado, Hardy (DJ Taylor 46), Fishburn. Subs - Simons, Boyd, M Bell.
Referee - Nathaneal Cox
Assistant Referee 1 - Daniel Mcdonald
Assistant Referee 2 - Tim Eagles
Attendance - Approx 100