Three-time world champion Selby looked set for a comfortable time of it when he raced into a 4-0 lead in the afternoon session, posting breaks of 130 and 96 along the way.
But Gould responded by taking each of the next four frames, making a clearance of 131 in frame eight, to leave the match level heading into the evening's action.
Gould then led 5-4 and 6-5, and after Selby levelled via a 113 break and then went 7-6 up, the world number 53 produced a 107 break to even things up once again.
Selby again edged ahead, only for Gould to hit back once more, posting a break of 96, to set up a decider.
And it was the Leicester cueman who subsequently emerged victorious as he won his 10th successive ranking final.