The Windwards rushed to a comfortable eight-wicket win over Barbados at Morant Bay; Guyana beat Jamaica on a faster strike rate at Chedwin Park after bad light and then rain stopped play while the Leewards edged Trinidad and Tobago by eight runs at Emmett Park.
Barbados were routed for a paltry 107 in 42 overs with No.10 batsman Derek Bishop making the topscore of 27 not out and captain Rohan Nurse getting 22.
Joakim George (3-19), Alston Bobb (2-14) and Cozier Charles (2-17) were the Windwards' most successful bowlers.
In reply, Kaschako Cupid (35 not out), Garvin Roberts (31) and Sergie Fedee (20 not out) carried the Windwards to victory as they made 109 for two in 36.3 overs.
On Thursday, Barbados defeated Jamaica by three wickets at Kensington Park.
Jamaica, who won the toss and batted made 179 for nine in 50 overs with lower order batsman Omar Campbell getting the topscore of 40 and captain Donovan Pagan scoring 35.
Jemario John was Barbados' leading bowler with three for 31 while leg-spinner Kadoye Pantophlet captured two for 27 off his ten overs while left-arm spinner Derek Bishop took one for 15 off 10 overs.
In reply, champions Barbados faltered after Dwayne Smith had made 32 and Rohan Thompson was run out for 16 and were in a precarious position of 90 for five as captain Rohan Nurse made only 12.
However, a sixth-wicket stand of 72 between hard-hitting left-handed batsman Ryan Nurse, who made 56 not out with five fours and two sixes and all-rounder Pantophlet (24) revived the Barbados innings.
Fast bowler Antonio Thomas and Man-Of-The-Match Nurse saw Barbados safely home at 182 for seven in 47.3 overs.
Off-spinner Arden Frew was Jamaica's best bowler with three for 27 off eight overs.