Keith Curle admits Carlisle's habit of conceding early in the second half of games is "doing his head in".

The Blues again slipped up soon after the restart as they fell to a 1-0 defeat to Coventry.

Mark McNulty capitalised on a defensive misjudgment to score the only goal on 50 minutes.

Although keeper Jack Bonham later saved a McNulty penalty, United were unable to find a way back in their final game of 2017.

Carlisle, who fell to 13th in League Two, have now conceded inside the first 11 minutes of the second half in four of their last five games.

Manager Curle said: "Frustration is probably a very mild term. It's doing my head in.

"We need to be more defence-minded after the break. All oppositions do after the interval is put the ball in and around you and hope for a mistake. At the minute they're getting them off us.

"I don't think it's tactical. I don't send any player out to make a mistake in the first minute of either half. But it's something we've mentioned."

Curle felt the build-up to McNulty's goal, when United failed to keep the ball in play then reacted slowly to Coventry regaining possession, was just as culpable as the final ball over the top which Clint Hill allowed to bounce before McNulty fired home.

"It was down to the conditions, losing the flight of the ball because of the wind, [but] before that our shape wasn't right. You then give a striker of that quality an opportunity in the box, and you're going to be under pressure," the manager said.

McNulty's finish was enough to clinch victory for the Sky Blues in the final game of 2017, in front of a 5,807 crowd - including 847 travelling fans - at Brunton Park.

Bonham kept out the frontman's spot-kick on 75 minutes after Mike Jones had fouled Jordan Shipley.

But Carlisle created few clear-cut chances in the second half and are now six points adrift of the play-off places. Mark Robins' men moved up to fifth.

"I thought we lacked a little bit of quality in the final third," Curle said.

"I don't think there was a lot in the game, but we didn't move the ball quickly enough to cause them a problem. We needed to up the tempo. In the latter stages we were moving the ball quicker but we weren't making the runs from midfield.

"The changing room's hurting, they knew we were on the up. We didn't do enough to earn the win."

Curle suggested United could have had a penalty in the first half, after Carlisle appealed for handball when Tom Davies blocked a Hallam Hope shot.

"In my book, if you're raising your hands in that area, you'd have to say it's an unnatural position, and the ball made contact with his hands as far as I could see," Curle said.

But the manager, whose side go to Mansfield on New Year's Day, added of United's display: "There was a spark missing.

"This is when we need to use the squad now, with a quick turnaround of fixtures. There will be changes to the team selection because of the shortage of rest and recuperation period between games.

"We've got players chomping at the bit, and it's a good opportunity for them to come in, step up to the plate, grab the opportunity and put in a performance that merits them staying in the team."

Curle added that he is set to meet United's board on Friday, where his January transfer budget plus his own contract situation will be among the subjects under discussion.