Jamaica Tallawahs, set a victory target of 134, secured the win off the final delivery.
Captain Gayle hammered 51 from 25 balls to top score for Jamaica Tallawahs, while Chadwick Walton scored 28 from 35, and Danza Hyatt a run-a-ball 25 not out.
Trinidad and Tobago Red Steel’s skipper Dwayne Bravo and Kevon Cooper ended with two wickets apiece.
Earlier, Trinidad and Tobago Red Steel sent in to bat scored 133 for eight off their allotted 20 overs.
Bravo top scored with 29 from 16 balls, while his brother Darren supported with 27 from 29 balls and Ross Taylor hit 20 from 21 deliveries.
Gayle had best figures for Jamaica Tallawahs.
He ended with two for 24 off his allotted four overs, while David Bernard, Andrew Richardson and Andrew Russell bagged a wicket each.
As a result of the victory, Jamaica Tallawahs finished the preliminary round in second place on 10 points and earned the right to meet third place Barbados Tridents in the second semi-final on Friday.
Guyana Amazon Warriors, who finished atop the points’ table courtesy of net run rate, and fourth place Trinidad and Tobago Red Steel will contest the first semi-final on Thursday.
