Jon Mellish scored a hat-trick as rock-bottom Carlisle stunned promotion-chasing Peterborough with a shock 3-1 success in Sky Bet League One.

Midfielder Mellish, who had only previously scored twice all season, did the damage as Paul Simpson’s basement boys bagged just a sixth win of a torrid campaign.

Mellish rose unchallenged to meet substitute Jordan Gibson’s cross after Posh switched off from a Dylan McGeouch short corner as Carlisle took a 27th minute lead.

The same man doubled their advantage three minutes into the second half when he struck an impressive volley past Posh goalkeeper Jed Steer, following a weak defensive header from England Under-20 defender Ronnie Edwards.

Mellish was not done there, completing a memorable treble in the 58th minute with another spectacular left-footed volley after the hosts failed to deal with a McGeouch cross.

Posh quickly hit back as captain Harrison Burrows slammed a 61st-minute shot through a crowd of players from the edge of the box but that was as good as it got as Darren Ferguson’s men flopped.

Substitute Jonson Clarke-Harris fluffed a glorious chance to cut the arrears further, before also being denied by the bar late on as the courageous Cumbrians stood firm.