A Joe Murphy goal midway through the second half sent the Jersey Football Combination into the quarter-finals of the Inter-League Cup.
Murphy struck with a low shot to give the island side a 1-0 win over the Essex and Suffolk Border League.
Matt Rawlings had earlier wasted a golden chance to give Jersey the lead, hitting the bar from close range.
The winners of the tournament will represent England in the Uefa Regions Cup.
Jersey Football Combination manager Craig Culkin said: "I thought we were worth the victory in the end but made it difficult for ourselves in the first half.
"The boys are really pleased and we had to really dig deep for that performance today.
"We learned a great deal about ourselves today and I think that will stand us well going into 2012 and the last eight of this competition."