Shearing his 15 sheep at the weekend in 9min 59s, he was 39s ahead of teammate Simon Bedwell, and more than a minute-and-half quicker than either of the Kiwis, who arrived only days before what was the only test against Scotland on the tour.
Mitchell also posted the best board and pen judging points, as Scotland won comfortably by more than 11 points.
Hastings-based Smith and brother Matthew also qualified for the four-man Scottish Blackface Championships open final, which was won by Bedwell. New Zealand-based Scotsman and world champion Gavin Mutch was second, and Matthew Smith, having been top qualifier from the semifinals, was third.
Northlander Brya Harrison was third in the Scottish Blackface junior final.
The next test for Golden Shears and New Zealand Open champion Rowland Smith and his teammate from the South Island will be against England at the Lakeland Shears in Cockermouth, Cumbria, next weekend.
Results from the 2013 Lochearnhead Shears and Scottish Blackface shearing championships:
International (15 sheep): Scotland 83.25pts (Hamish Mitchell 9.39, 39.68pts; Simon Bedwell 10.38, 43.57pts) beat New Zealand 94.92pts (Rowland Smith 11.38, 46.7pts; Tony Coster 11.51, 48.22pts).
Open final (20 sheep): Simon Bedwell (Scotland) 12.59, 47.35sec, 1; Hamish Mitchell (Scotland) 13.00, 48.65pts, 2; Matthew Smith (New Zealand) 13.26, 51.45pts, 3; Rowland Smith (New Zealand) 14.38, 54.3pts, 4.
Senior final (10 sheep): Dafydd Jones 9.21, 38.45pts, 1; Scott Wilson 9.05, 38.75pts, 2; Stewart Kennedy 10.41, 41.25pts, 3; Sandy McKellar 9.07, 41.55pts, 4.
Intermediate final (7 sheep): Alister Shaw 7.30, 35.66pts, 1; David Gibson 7.47, 37.35pts, 2; Brian Mundell 7.55, 38.18pts, 3; Lewis Harkness 9.51, 41.55pts, 4.
Junior final (4 sheep): Adam Karvo 5.55, 22.33pts, 1; Adam Mitchell 5.42, 24.03pts, 2; Brya Harrison (New Zealand) 7.28, 27.06pts, 3; Jonathan Malloy 5.40, 30.21pts, 4.