The contest, played in awkward conditions given the inclement weather, was all square at half-time, 0-3 apiece.
Cian Davis and John Lyons points bookended a David Manley free giving Douglas a 0-5 to 0-4 advantage after the restart. However, Coholan’s subsequent contribution was to prove decisive.
Advancing with purpose, Simon O’Brien released Dan O’Reilly on the overlap via an incisive handpass.
The latter thought about flicking the ball over to level but saw Coholan moving menacingly inside him.
O’Reilly palmed to his left where Coholan rose to fist over goalkeeper Andrew Cullinane despite the admirable efforts of Daire O’Shaughnessy to recover the situation for Douglas.
In fairness to Douglas, Sean Walsh and David Hanrahan responded effectively and they were on par again, 1-4 to 0-7, on 42 minutes.
Hanrahan’s equaliser, in particular, could have been a momentum-shifter. Yet, Douglas added just a single point thereafter, courtesy of Hanrahan again six minutes from time.
Carrigaline, in contrast, boxed cleverer in the final quarter, stitching on 0-4 via a Tony Murphy free, Coholan, an instinctive half-volley from Peter Mullane and a 56th minute free from Jamie de Puis to run out three-point victors.
“We focused on being solid as a unit, particularly defensively,” Carrigaline manager Martin O’Reilly explained afterwards.
“And we are delighted with that aspect of our performance.
“We didn’t concede any goal and when that’s the case your defence has generally done its job.
“It was obviously not a flawless performance. But we got there in the end.”
They did, but Carrigaline could have trailed at the interval were it not for Douglas’s indecisiveness in attack.
James O’Mahony, a counter-attacking wing-back, and powerful midfielder Éanna Mulrooney, generated a host of offensive plays from deep-lying areas.
However, transitioning and developing those plays efficiently proved tricky due to a shortage of options in front of them when they had their heads up in search of an outlet. But credit the touch-tight defending of Carrigaline too.
Mullane and Johnny Farrelly exchanged scores prior to Manley pointing a ninth-minute free as Carrigaline led 0-2 to 0-1.
Yet, O’Reilly’s charges went 21 minutes without scoring until Simon O’Brien equalised for them in added-time at the end of the opening period.
Cullinane was forced into an excellent save from Coholan on 13 minutes as the attacker sniffed a major.
Still, Douglas generally dominated this block of time but only had points from Cormac Dineen and Walsh to show for their troubles which will have frustrated them.
And Coholan’s goal ensured they would pay the price.
A Coholan (1-1); P Mullane, D Manley (frees) (0-2 each); S O’Brien, T Murphy (free), J de Puis (free)(0-1 each)
S Walsh, D Hanrahan (0-2 each); J Farrell, C Dineen, C Davis, J Lyons (0-1 each)
K Daly; S Dineen, K Kavanagh, C Murphy; G Harrington, C McSweeney, S Griffin; P Mullane, S Dwane (capt); D Manley, B Pope, D O’Reilly; A Coholan, T Murphy, S O’Brien
D Moran for Dwane (b c, 27), D Twomey for Manley (38), C Cremin for O’Reilly (42), J de Puis for Moran (51)
A Cullinane; E Nyhan, D McSweeney, D O’Shaughnessy; J O’Mahony, J Lyons, C Sheehan; C Dineen (capt), E Mulrooney; M Bartley, C Davis, D Hanrahan; B Cuthbert, S Walsh, J Farrell
Mark O’Callaghan for Cuthbert (47), Darragh Kelly for Davis (54)
Ian McCarthy (Bandon)