Alan Dunbar defeated Austrian Matthias Schwab on the final hole to win the British Amateur Championship at Royal Troon on Saturday.
The Rathmore player had gone down the last all square with Schwab after 35 holes of their 36-hole contest.
Schwab had led by one hole after the first 18 holes of their decider.
Dunbar has qualified to play in the Open at Royal Lytham and next April's Masters at Augusta by virtue of his victory on the Scottish seaside links.
Dunbar, 22, is the first Irish player to win the championship since Brian McElhinney in 2005, while Belfast player Michael Hoey also won the title in 2001.
He reached the final by beating Scotland's Paul Ferrier 3&2 on Friday, having earlier defeated Robert Karlsson of Sweden 3&2 in the quarter-finals.
Dunbar beat Denmark's Patrick Winther 7&6 in the third round before sealing a two hole win over Paul Barjon of France on Thursday afternoon.