Set 228 for victory against Northamptonshire at Les Quennevais, the Jersey lads were bowled out for 101 in 40.4 of their scheduled 50 overs.
Tom Worthington was the leading Northamptonshire bowler with four wickets for 19 runs in 8.4 overs.
Richard Blackburn and James Perchard both took three wickets as Northamptonshire lost nine wickets on the way to their total, Simon Caunt impressing with 95 runs.
Jersey coach Peter Gough said: ‘Our bowling and fielding was again good and the difference was they had batsmen who knew how to accelerate to score runs.
‘It was tough for us batting, our players faced probably the quickest bowlers they have faced to date.
But it’s a learning experience and we are giving a good account of ourselves.’ Captain Tom Wherry took three good catches fielding in the covers.
Middlesex made it two wins in two days after defeating Hampshire by 78 runs.
Kabir Toor made 93 and Adam London 45 as Middlesex closed on 221 for 6.
London excelled with the ball too, his ten overs resulting in five wickets for 29 runs as Hampshire were all out for 143.
Guernsey suffered a second heavy defeat going down by 143 runs against Sussex.
Among the runs were Ben Brown (53), Michael Norris (46) and Billy Harris (43), the latter pair sharing an eighth wicket partnership of 65 off 42 balls enabling Sussex to close on 255 for 8.
Guernsey’s John Warr claimed two wickets for 36 runs in a nine-over spell while Chris Dravers returned 2 for 5 in six overs.
Sussex’s bowlers – Luke Tomsett (1 for 10 in 5 overs), Josh Fleming (7 overs 6 maidens 2 for 2) and Luke Barnard (9 overs 4 maidens 2 for 13) – also impressed.
Yorkshire, like Sussex and Middlesex, also made it two wins in two games after they beat Wales by nine runs.
Yorkshire posted 152 for 9 with Wales all out for 143.
James Finch took four Wales wickets for 24 runs.
