Guernsey topped their group after the first day of action in the ICC European Division One Twenty20 on Tuesday.
After demolishing Norway in their opening match, the Sarnians struggled to reach the modest 97-7 set by Croatia in their 20 overs at College Field.
Guernsey lost wickets cheaply and found themselves requiring 31 from the last four overs with six wickets down.
Steady batting from David Hooper and some brutal sixes from Jamie Nussbaumer saw them home with an over to spare.
Captain Stuart Le Prevost, who was the island side's highest contributor with 34 runs, said: "In fairness to them, I thought they bowled pretty well. They were bowling in decent areas on that pitch.
"It was a slower than the KGV pitch, which is possibly to our detriment. They had already played here so they obviously knew the wicket better but that's no excuse. We play here week in week out.
"We probably should have made easier work of it but we're happy with the win anyway."
He said: "The win is the main thing. There was a really good performance from Dave Hooper who came in a bit lower down the order and batted really well. He's shown great promise through the winter and he's got his chance and taken it.
"Jamie Nussbaumer strikes a cracking ball as we saw one sail into the trees. On the whole pretty pleased and pleased the young guys featured as well."
The three wicket win put Guernsey top of Group A, ahead of Italy on net run rate after the Italian side secured wins over Croatia and Austria.