Barnsley 0 Carlisle United 3: Thirty-three years, but it was worth the wait. Carlisle United’s first visit to this ground since 1986 brought a superb, opportunist and comprehensive Carabao Cup victory, and they will do well to achieve many more enjoyable days on the road than this in 2019/20.

A first-half when they snatched the lead then developed into a comfortable advantage, when Jack Bridge’s penalty and a Nathan Thomas goal added to their snaffled opener from the outstanding Harry McKirdy.

Yes, Barnsley’s side was more makeshift than their fans are used to seeing, but this remained a fine effort from Steven Pressley’s team, who were hungry in midfield and bothered the hosts regularly in attack. Ryan Loft was a useful and willing target man in between Thomas and McKirdy and in general it seemed to matter more to the Cumbrians, who will hardly turn down the chance of a cup run in this time of book-balancing.

Barnsley’s sloppiness cost them, but so did United’s eagerness to pounce. Nobody better typified this attitude than McKirdy, who read a defensive mistake to score the first and showed purposeful running to create their second (a penalty for Bridge). Harnessing the former Aston Villa man’s talent this effectively in the league, when battle tends to be more urgent, is essential.

Inflicting this on Mansfield is the challenge on Saturday. In the meantime, they can enjoy this welcome night over the Pennines, which earned a second-round trip to Rochdale. While Barnsley’s Daniel Stendel made seven changes - a sign of his priorities as a newly-promoted Championship team - Pressley’s alterations were more limited, Jack Iredale in for Jon Mellish at left-back and a start up front for Loft in place of Olufela Olomola.

Hallam Hope’s place among the subs was another positive piece of news at a time United are still a centre-forward short. Carlisle have been good on the road in this competition in recent years and this was a chance to put some early colour in their campaign.

Oakwell was a fresh sight for many of their fans and thankfully Barnsley did not ruin this sense of novelty. They created a chance after 36 seconds, Conor Chaplin denied by Adam Collin, and a few further half-openings which the Blues coped with.

But things had not begun at Championship pace and while Barnsley were initially able to switch play well, and turn defence into attack quickly, their early finishing was wasteful and Carlisle’s pressing in the home half then started to punch out opportunities.

The first of several involved Thomas seizing the ball and feeding McKirdy in an inviting position, but his touch allowed Aapo Halme to get back. Carlisle were keener than normal to send the ball up the pitch, given the tall figure of Loft, but they also worked some useful angles down the left, where Iredale was overlapping well on his full debut.

Then came a particularly urgent spell which eventually yielded the opener. First, Loft was clean through but denied by Brad Collins. The home keeper then saved from Thomas at close quarters and from a deflected McKirdy dipper as the Tykes survived the resulting corner when it ricocheted.

United then got the gift they couldn’t pass up, as Halme left a pass alone, not noticing McKirdy behind him. He planted it low past Collins and suddenly there was a song of “Championship? You’re having a laugh,” from the away end.

To begin with the home side did not play as if affronted by this mockery. Barnsley’s fans grew frustrated with their team’s play from the back, especially when passes went loose and United’s midfielders were on to them, sometimes drawing fouls. Collin saved sharply from Chaplin but then Carlisle came very close to a bonus second, as a free-kick bounced and Loft, on the floor, extended a long leg and hooked it over Collins and against the bar.

United looked untroubled in this period and it was only right at the end of the half that Barnsley truly stirred. Carlisle, though, survived as Chaplin rounded Collin but checked back into retreating green shirts, and Byron Webster, who had a secure night, was on the line to deflect Jordan Williams’ follow-up away.

The next task appeared to be to see through another 45 minutes against a home side who would surely come back. Barnsley, early in the second half, looked to step things up down the wings where the pace of Mallik Wilks and Mamadou Thiam were the intended weapons.

A build-up of pressure saw Cameron McGeehan and Cauley Woodrow shoot wide, while a sequence of corners was cause for concern as United were pushed on to the defensive. Frustration remained in the South Yorkshire air when McGeehan sent the ball out from a hopeful position, but Carlisle still needed a respite.

On 58 minutes, they got one. Iredale’s sharp feet fed the dynamic McKirdy and he raced in from the left, going down under Mads Andersen’s challenge as he bore into the box and ref Ben Toner was quick to give the penalty even though Thomas put it in the net as it broke. Bridge dealt with any potential for controversy by stroking in the spot-kick.

The Blues now had the benefit of daylight. A Williams cross, glanced by Woodrow, hit the post for Barnsley before Stendel made a double change on the hour - and then Carlisle, remarkably, were further in front: Thomas, this time, showing clinical intent as he picked up the ball, ignored Loft to his right and drove past his man to shoot across Collins.

Could it be that United were not just inching through but positively striding into the second round? Unlikely as it sounds, it could. Olomola made a combative contribution from the bench, Hope also returned to action and even Aaron Hayden got a cameo up front as Barnsley failed to seriously endanger Collin’s net and the Blues hit the post towards the end.

On a night where goalline technology was being used, this had become anything but a game of fine margins.

Barnsley: Collins, J Williams, Andersen, McGeehan, Woodrow, Chaplin (Bähre 60), Styles (Miller 73), Pinillos, Halme, Thiam, Wilks (L Thomas 60). Not used: Radlinger, B Williams, Sibbick, Moon.

Booked: Styles, Andersen, Bähre.

United: Collin, Elliott, Iredale, Webster, Knight-Percival, Jones, Scougall, Bridge, McKirdy (Olomola 65), N Thomas (Hope 76), Loft (Hayden 81). Not used: Gray, Mellish, Branthwaite, Sagaf.

Goals: McKirdy 24, Bridge 58pen, Thomas 64.

Ref: Ben Toner.

Crowd: 5,208 (385 Carlisle fans).