The Saints were largely indebted to the efforts of former Island player Andy Dewhurst, who scored 67 runs, which also ended up being the final margin of victory.
Defending their 159 runs, St Ouen bowled their opponents out for just 92, as Richard Anthony, George Alabaster, Henry Wickham and George Cousins took two wickets apiece.
Also at FB Fields, 2013 champions Grant Thornton Beeches eased past nine-man Ashburton St John Spitfires courtesy of a seven wicket triumph.
Damian Maltwood (42 runs) top scored for the defeated, as Spitfires could only reach 124 runs before being bowled out in exactly 19 overs. Island spinner Rhys Palmer did the damage for Beeches, taking four wickets for 20 runs in his four overs.
Duncan Ellis (43 runs) and James Turnbull (30 runs) led the charge as Beeches surpassed their target with 9.2 overs – and seven wickets – to spare.
Bailiwick Express have also secured their place in the last-eight of the knock-out competition, after beating RBC International Royals by 44 runs at Les Quennevais. Adam Sutton (51 runs) and Fraser McInnes (78 not out) top scored for Bailiwick as they reached 179 in their allotted 20 overs.
Openers Amey (31) and Phil Maletroit (36), and number three bat Abhishek Nagar (31) all made decent contributions but, in the end, Royals were well short of their target as their overs expired. Also at Les Quennevais, Ashburton St John Renegades beat Tamarind by eight wickets (no scorecard received).
The JEP KO Cup second round concludes with four matches on Tuesday.
BAILIWICK EXPRESS v RBC INTERNATIONAL ROYALS
Bailiwick Express won by 44 runs
Bailiwick Express
Total (for 5 wkts) 179
Royals
Total (for 4 wkts) 135
ST OUEN SPRINGFIELD v HAUTLIANS
St Ouen won by 67 runs
St Ouen
Total (for 6 wkts) 159
Hautlians
Total (all out) 92
ASHBURTON ST JOHN SPITFIRES v GRANT THORNTON BEECHES
Beeches won by 7 wkts
Spitfires
Total (all out) 124
Beeches
Total (for 3 wkts) 125
ASHBURTON ST JOHN RENEGADES v TAMARIND
