Castletown failed to win the Menorca International 20/20 tournament by just nine runs.
They restricted favourites Barnsley to 152 for 9 from over 20 overs.
Ollie Steriopulos turned in a great bowling display with five wickets for 18 runs, including a hat-trick, and Wicus Wessels made 23.
However, their hopes were shattered by Paul Hepworth who took three for 17, including another hat-trick
In a tight finish the Manx side finished on 143 for eight.