Simpson: 'Lapse' cost Carlisle United at Oxford United

But the Blues boss also admitted his side are not currently dangerous enough in the final third.

Mark Harris’ 76th-minute goal was enough to consign Carlisle to defeat in their first away game of the League One campaign.

Simpson said it was a close call as to whether the Oxford frontman was onside as he got behind the Blues defence.

But the manager stressed that the hosts’ attack should not have got that far in the first place.

“Unfortunately if you have a lapse in concentration, however minimal it is, you’re going to get punished the higher you go up,” said Simpson.

“We’ve only gone up one level but we’ve been punished here for a momentary lapse where we’ve allowed the runner to go, we haven’t tracked him and we haven’t talked, and these are things you get punished for.

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“It looks such a scruffy goal to concede, it’s a horrible one to give away. You simply can’t afford to make the mistakes that we did.

“It’s a case of a straight ball down the line, we didn’t track a runner, and we concede a goal.

“It’s a scruffy finish but the striker won’t care about that. It shouldn’t have been allowed to happen, it’s as simple as that.

“We don’t need a lesson [about these things] – we know. We know what happens. We ‘ve found out about it again today, that’s the problem, through a momentary lapse, not communicating, not tracking runners, and you get punished for it.”

Carlisle had started the game brightly but struggled to create chances against Liam Manning’s side.

Jon Mellish tackles Marcus Browne (Image: Richard Parkes)

It left them frustrated after their long trip and continued to highlight their shortcomings in attack.

“I just don’t think we fully committed to it, I don’t think we went the full hog and really went for it," said Simpson of their efforts in the final third.

"I thought we were a bit tentative. Maybe that’s human nature, maybe that’s what happens when you’re just wanting that first victory. Because we’re like the supporters, we want it as much as they do.

"Maybe that’s what it is, I don’t really know, but we’ve got to get over it, we’ve got to go gung-ho, have a go, try and get ourselves goals, get bodies into the box to go and get it.

"We did so many good things today, we won the ball back in good areas because we pressed well, we had a good plan about it. Unfortunately we haven’t done enough to get anything from it."

Simpson’s team included a first league start since December for Taylor Charters in midfield, while Ryan Edmondson got his first start of the season up front.

Initially Carlisle seemed to be well in the game against an Oxford side with just one home win to their name in League One since January.

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“[At half-time] I was really pleased. I thought that first 45 minutes was as well as we’ve played," the manager added.

“Again, that’s without troubling the goalkeeper.

“We know we put them under pressure, we nicked it in good areas, we had some good transitions, but you have to be ruthless. If opportunities come you have to take them.

“I said to Gav [Skelton, assistant manager] in the first half that we were on top and you have to make the chances count when that’s the case.

“We had three really good opportunities in the first 15 minutes where you just then need that little bit of quality to finish them off better.”

Paul Simpson, right, issues instructions (Image: Richard Parkes)

Simpson admitted Carlisle must improve in front of goal but was also adamant that his side’s display in general offered some encouragement.

“Unfortunately people only look at the result and you get nothing for the performance,” added the manager, whose side host Wigan Athletic on Tuesday night.

“We know that we did a lot of good things, sadly we’ve got nothing from it and in a week or two people will just look and see a 1-0 result away from home where you’ve lost and they don’t care about the performance.

“But we’ve shown there’s things there we can build on and there’s also things we’ve got to improve on.”