Scores: Trinidad and Tobago 193 for five from 50 overs; Jamaica 194 for four from 48 overs.
Points standings after the third round: Leeward Islands six points from three matches, Guyana four from three, Windward Islands four from three, Barbados two from three, Jamaica two from three and Trinidad no points from three.
Jamaica lost the wicket of captain Donovan Pagon for four before opening batsman Damion Gray and Danza Hyatt made a partial recovery with a good 44 runs second wicket partnership. Hyatt went for 25 and two balls later Andre O'Sullivan fell without scoring to leave Jamaica reeling at 53 for three.
Forrest who came in at the fall of Hyatt's wicket entertained the spectators with an array of strokes posting an unfinished 121-run stand with Omar Campbell (39 not out) to pilot the home team to victory.
At Kensington Park:: The Leeward Islands beat Barbados by the narrowest of margins in a nail-biting finish. Scores: Leeward Islands 150 from 47 overs (Zack Kenworthy 38, Austin Richards 33; Derek Bishop 5-8, Ryan Nurse 2-33); Barbados 149 for nine from 50 overs (Rohan Nurse 45, Jason Crawford 38, Dwayne Smith 12; Chaka Hodge 3-28, Anthony Martin 2-20, Loy Weste 2-21).