A goal midway through the second half earned the Highlanders the three points at a chilly, windswept Glenesk Park this afternoon.
Playing against the wind in the first half, the young Tangerines opened brightly and did well to hold their physically much stronger opponents in a goalless first half.
Apart from Rutherford clipping the United bar from a free-kick, and a David Gray effort being palmed round the post by Smith, the visiting keeper, goalmouth action was scarce.
There was a bright start to the second half as Gibson kept out a Zander Sutherland shot at one end, whilst Matti Flynn immediately scooped a shot over the bar from David Goodwillie's pass at the other.
Little was seen of United as an attacking force thereafter and midway through the half, Rory McAllister's diving header from a Chris Sutherland cross proved decisive as Caley Thistle eased to victory.
United: Gibson, Flynn, Gray, Burnett, Donnelly, McMechan. O'Hara (Fleming 62), McCord, Feeney, Goodwillie, Russell (Collins 77). Sub not used: Andreoni.
Inverness CT: Smith, Rutherford, Taylor (Jarvie 22), Gibb, Kerr, Soane, C Sutherland, McAllister, Donald, B Clark, A Sutherland. Subs not used: McIntyre, Watson, D Clark.
Referee: S Pullar