The first two games of the Steve Evans era had gone superbly for Mansfield, picking up wins against Crawley and Blackpool at the One Call Stadium last week.
And going into Saturday’s game away at Carlisle, Mansfield had only conceded 20 goals in 18 games this season for one of the best defensive records in the league.
But that record fell apart on Saturday as a very poor defensive showing saw Carlisle knock in five goals in a 5-2 defeat.
After Mansfield had taken an early lead, the first three Carlisle goals all came in similar fashion, with headed goals from crosses. The first goal was a cross following a short corner that found Jason Kennedy completely unmarked in the middle to head in from six yards.
From the video it is hard to tell who lost his marker as no one was near Kennedy - simply awful marking.
For the second goal, Charlie Wyke got goalside of Krystian Pearce to loop a header over Shearer and for the third goal, Wyke rose above the returning Lee Collins to head home.
It was poor defending for all three goals that left the Stags shellshocked and you just can’t defend like that and expect to win football matches.
To compound matters, the referee then awarded Carlisle a soft penalty for handball which looked harsh in real time and just as harsh looking at the video from two different angles.
Wyke converted underneath Shearer to complete his hat-trick and make it 4-1.
Despite all that, Mansfield weren’t finished and pulled it back to 4-2 when Danny Rose fired home from seven yards via a deflection after Matt Green did well to knock down an Ashley Hemmings cross.
Pearce should have made it 4-3 but somehow his close range shot was saved on the line by the keeper.
But in stoppage time Carlisle scored again when Reggie Lambe’s shot from the edge of the box, which was tamely heading straight at Shearer, deflected off Benning and into the net.
Early in the game, Mansfield had taken the lead when Pat Hoban headed home from six yards from a fine Chris Clements corner for his fourth goal of the season.
Carlisle deserved their win and go to the top of the league.
They look a very good side, but the Stags have to defend a lot better than they did, both in the middle and stopping crosses coming in.
So there is much work for Steve Evans and Paul Raynor on the training ground to get the defending right.
Against Crawley and Blackpool, Rhys Bennett and Krystian Pearce formed a solid central defensive pairing with Mitch Rose filling in at right back.
With Lee Collins returning from injury at Carlisle, Evans shifted Rhys Bennett to right back and Mitch Rose into midfield.
Evans has made it clear he wants to give all players a chance before January so that he can assess them and it’s likely that Alex Iacovitti will get a game soon, on his return from suspension, as will the other loanee, Kyle Howkins, once he recovers from a knee injury.