Greg Lobban surprised top seed Julian Illingworth to win the Indian Summer PSA Securian Open at the Commodore Squash Club in St Paul, Minnesota.
The 22-year-old from Inverness won the final of the PSA Challenger 5 event 11-1, 11-5, 12-10 to clinch the fourth PSA World Tour title of his career.
Both Lobban and Illingworth, the nine-time US national champion, had reached the final without dropping a game.
And the Scot kept up that 100% record with a strong display in the final.
Lobban, with a world ranking of 73, beat Cameron Stafford of the Cayman Islands, America's Adrian Leanza and the Australian Zac Alexander on his way to the match with Illingworth.
He goes into this week's Life Time Chicago Open as fourth seed, the main draw of which begins on Thursday.
He plays England's Robert Downer in the first round.