United faced Borough in round two of this season's Cumberland Cup at Frenchfield Park on Tuesday night.
United turned on the style as they romped into a first half four-goal lead but Borough played their part and earned their notch on the scoresheet when McCullough smashed home a penalty just before the break.
Substitute Luke Lloyd stole the show in the second half with a ten-minute hat-trick, and the young Blues created more chances as the rain poured down and the conditions worsened.
It started well for Carlisle on the night when McCarron led a charge down the left flank with just six minutes on the clock. He picked out Miller, who fed it to the edge of the area, and Keighran Kerr was on hand to finish it off.
United used the same avenue of approach in their next attack with Brockbank overlapping to get into a crossing position. His delivery skipped up off the surface and an unfortunate defender could do nothing as he sliced it into his own net.
The Blues looked confident with their two-goal advantage and Dixon did well to beat his man and feed the ball inside for McCarron to shoot. He caught it well but he couldn't keep it down.
Borough stopper Paul Flitton had to be at his best as United stayed on the front foot and a cross from Olsen found Kerr on the jump. His header was going in until the keeper leaped across to make the save.
Good pressure was made to tell on 21 minutes when Brockbank once again got past his man. It was heads in hands all round for the visitors as another scuffed clearance rattled into the roof of the net for a second own goal of the night.
The Carlisle lead was extended further just past the half hour when a blocked shot from Olsen ran kindly for Jaic Miller. He got his head over the ball and smashed it into the bottom corner.
Flitton was excellent again between the Borough sticks when Olsen and McCarron exchanged passes to leave Miller with another clear sight of the target. He did everything right but the keeper readjusted to make an excellent save which brought a round of applause from the crowd.
The visitors deservedly got on the scoresheet on the stroke of half time when they were awarded a penalty following a good spell of pressure. Liam McCullough stepped up to take it and he left Ashton with no chance as he crunched a powerful effort into the top corner.
Both sides kept the ball well after the break but Carlisle went close when Dixon sent Kerr through with just Flitton to beat. He opted for power and was disappointed to see his shot rebound away to safety off the crossbar.
The woodwork was in play again as the young Blues beat the offisde trap with Dixon right at the heart of the move. He went through two challenges and slotted a shot under the keeper only to see it collide with the post.
Kerr doubled his tally for the night when he finished well from the edge of the area, but substitute Luke Lloyd grabbed the headlines with a fantastically executed hat-trick from a devastating ten-minute spell.
His first was a crisp finish following more good work from Dixon, and his second came when he latched on to a great crossfield ball from Cowburn. He finished off the scoring on the night from close range when he poked a neat ball from Kerr into the waiting net.
Lee Ashton earned a pat on the back with a stunning save late in the day, and there were plenty of handshakes and smiles when the whistle blew to signal the end of a very enjoyable encounter.
United - Kerr (6 & 64), own goal (7 & 21), Miller (34), Lloyd (78, 82, 88)
Borough - McCullough (42 pen)
Carlisle United - Ashton, Olsen (Cowburn 66), Brockbank, Hutchinson, Taylor, Goldthorpe, Miller, Adewusi (Kelly 46), McCarron (Lloyd 66), Kerr, Dixon. Subs - Papa, Watson.
Borough - Flitton, Berry, Skaag, Rutherford, Watson, McAdam, Barton, Carter, McCullough, Marshalsea, McDonald. Subs - Hooper, Little, Thompson, Bezuszko, Melton.
Referee - John Mulligan