The Warriors won the toss and chose to field first, a decision which looked like the wrong one at the halfway stage of the game.
Former West Indies Under-19 representative Tristan Coleman was in destructive form for the Titans with a rapid 23 off just 10 balls including three sixes.
Cameos from Oshane Walters (20), Wayne Davis (18) and Jamaica Scorpions all-rounder Jamie Merchant (16) helped the Titans post a formidable 106-6 off their 10 overs.
Mikheil Silver (3-11 off two overs) and Andre McCarthy (2-21 off two overs) were the best bowlers for the Warriors.
Cornwall then got contributions from all their batsmen to eventually overhaul the Titans' total on the very last ball of the match reaching 107-4 off 10 overs.
Ockeeno Farquharson (29), Andre McCarthy (23) and Kerry Holness (17) were the main contributors while Jamaica Scorpions batsman Paul Palmer Jr and Captain Damion Ebanks chipped in with 13 and 13 not out, respectively.
Merchant took 2-21 off his two overs for the Titans.
The Risers took first strike after the Titans won the toss and elected to field first.
Delbert Gayle (35), Ricardo McIntosh (27) and captain Chadwick Walton (22) did the bulk of the scoring to help the Risers post 106-5 off their 10 overs.
Brian Buchanan (2-23 off two overs) and Errol Thomas (2-15 off two overs) were the best bowlers for the Titans.
In the Titans' turn at the crease, contributions from Sherdon Allen (33), Wayne Davis (22) and Albert Gopie (20) were not enough as they fell agonizingly short of the Risers total, finishing 102-6 off their 10 overs.
Fraser, who has 24 wickets in five first-class matches for the Jamaica Scorpions and West Indies A, was the pick of the bowlers with 3-24 from his two overs, including two wickets in the final over when the Titans needed 13 runs for victory.
He got the wicket of Jamie Merchant (2) off the second ball of the over before a six from Oshane Walters off the penultimate ball of the innings meant the Titans needed five runs from the last ball.
Fraser then dismissed Walters (8) off that final ball to seal the Risers’ second win of the tournament.
After the United Stars won the toss and elected to field, they bowled well to restrict the Titans to 81-8 off their 10 overs.
Sherdon Allen (36) and Oshane Walters (10) were the only Titans batsmen to reach double figures as West Indies U-19 representative Andel Gordon led the United Stars bowling with 3-10 off his two overs.
Dwayne Hamilton also took 2-21 for the United Stars.
The Stars reply never got out of first gear as only Jamaica Scorpions all-rounder Alwyn Williams was able to get to double figures with 16.
At the time the rain came down, the United Stars were teetering at 41-7 off 7 overs. There was no further play as the match was then called off with the Stars 18 runs short of their target via the Duckworth-Lewis method.
The aforementioned Grant produced an excellent spell of bowling, taking 4-9 off his two overs.
