Canavan’s final say
Bryan Horisk’s 28th-minute goal gave Errigal a 1-3 to 0-2 interval lead, and Carrickmore lost Ciaran McAleer to a straight red card in first half stoppage time.
However, they came storming back with scores from Gabriel Mccallan, Martin Penrose, Johnny Munroe and Ruairi Loughran to go level at the end of the third quarter.
Tommy Canavan edged Errigal back in front, but two Caolan Daly frees had Carmen ahead as the game slipped into added time. Damien McDermott then converted his third free before Darren Canavan slotted the winner.
Peter Harte and Ciaran McGinley were sent off late on, but both will be available for the decider.
That will be against Dromore, who remain on course to reach a fifth final in six years, or Killyclogher after they drew 0-5 to 0-5 in their semi-final.
Killyclogher went ahead early on with scores from Simon O’Neill and Leo Meenan, before Dromore drew level with two Eoin McCusker frees.
In a tight, tense second half, Simon O’Neill thumped over a long-range free four minutes from the end to tie it up again.