Jersey are World League Five champions, after a 44-run win in the final over pre-tournament favourites Oman.
Anthony Kay hit 60 not out for the hosts as they recovered from 51-4 to post 194-7.
Oman raced to 47-0 inside five overs, but when opener Zeeshan Maqsood was out for a quick-fire 43 the run rate slowed.
Ben Kynman took 4-10 as Oman struggled to 150 all out and their first loss of the week.
Both sides had gone into the match already guaranteed promotion to World League Four, just by making it into the final.
Jersey though were looking for revenge after losing to Oman in the group stage in a rearranged match. The original fixture had been abandoned because of rain, with the hosts in a strong position at the time.
Openers Peter Gough and Nat Watkins made a watchful start, having been put in to bat in slightly misty conditions, reaching 37-0 from their first 10 overs.
When Gough was bowled by Rajesh Ranpura, Ben Stevens and then Watkins both soon followed their skipper back to the pavilion as the hosts lost three wickets for three runs in the space of 14 balls.
Kay's innings, well supported by Corey Bisson (35) in particular, helped the home side out of a difficult situation to set a defendable target.
Oman's run-chase though started at a blistering pace, before Kay got the breakthrough dismissing Maqsood with a brilliant diving catch off his own bowling.
A day after taking 6-18 against Nigeria, Kynman was on form with the ball again, bowling accurately and with real pace to ensure the reply could not gather momentum.
Oman were eventually all out for 150 with 4.3 overs remaining, and Jersey's celebrations could begin.
Both sides will play in World League Four, in Los Angeles, later in 2016. Elsewhere on Saturday, Guernsey took third place in the tournament and preserved their World League status, beating Vanuatu by 19 runs at Farmers Field.
Tanzania and Nigeria join Vanuatu in relegation into regional continental tournaments.