The left-handed Jamaican sparkled once more with 51 off 31 balls but the Tuskers were restricted to 162 for three off 18 overs, chasing a revised target of 186.
Earlier, Ryan ten Doeschate unfurled a sublime unbeaten 121 to fire the Eagles up to 207 for seven after they were sent in at the Harare Sports Club.
They will now face Mountaineers in today’s final.
Facing an imposing target, Gayle and Tom Smith gave the Tuskers yet another breezy start by adding 67 off 48 balls.
Gayle smashed three fours and four sixes in his innings to dominate the stand before he fell caught and bowled by English medium pacer Peter Trego in the eighth over.
Smith, who made just 13, fell next ball and in-form Charles Coventry departed cheaply for 13, to leave the Tuskers on 97 for three in the 13th over.
Steven Trenchard’s whirlwind 31-ball 56 was not enough to get the Tuskers up to their target.
Ten Doeschate had earlier put on a one-man show, blasting six fours and eight sixes off 58 balls to lead the Eagles.
The Dutch all-rounder put on 89 for the first wicket with Englishman Rory Hamilton-Brown (26), which set the tone for the Eagles’ domination.
Gayle, shut out of the West Indies team because of an ongoing wrangle with the WI Cricket Board, finished the tournament with the highest aggregate of 291 runs at an average of 58.6.
