Meerut teenager Shapath reached his maiden final when he qualified on a shoot-off in fourth position out of the top six, raising hopes of India's first medal of the World Cup.
He could, however, manage a sixth place finish in the final, being the first to be eliminated, shooting 26 out of the first round of 30 targets in the finals.
Italy's former world and European champion Danielle Di Spigno displayed a double trap master class, hitting 78 out of 80 targets en route claiming the gold in a Finals World Record performance.
Earlier, Sampath finished fourth following a shoot-off to make it to the finals.
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He started on an indifferent note shooting just 24 out of 30 possible hits. He gained in consistency after that and maintained it till the end, shooting a perfect 30 in the second series and 27 in each of the next three series to be one of four shooters to finish with a score of 135.
Shapath won his shoot-off, getting the better of the much more experienced and former World Cup gold medalist Italian Davide Gasparini, shooting 22 to Davide's 21.