Motherwell dropped from second to third in the Scottish Premier League after a decisive defeat by Ross County.
Ivan Sproule opened on 34 minutes, striking a Rocco Quinn pass under Motherwell keeper Darren Randolph.
Sproule should have doubled County's lead shortly after the re-start, but made amends by setting up Richard Brittain to score on 70 minutes.
The home side cemented the result in the final minute, Iain Vigurs volleying home from close range.
It was a five-star performance from County that saw the SPL debutants move into the top six for the first time. And the win also extend their unbeaten run to eight games, from which they have taken 20 points - more than half their current total of 38.
The first chance fell to Motherwell, but it was almost their only opportunity of the game when Michael Higdon's shot was blocked in the second minute. County replied when Sproule volleyed over before both Vigurs and Quinn tested keeper Darren Randolph.
The breakthrough came on 33 minutes when Vigurs supplied Sproule, who ran powerfully towards goal and slid the ball past Randolph.
Sam Morrow came close to County's second when he had a shot deflected past and, just before half-time, Adam Cummins headed a free kick over the bar at the other end.
Early in the second half Chris Humphrey gave Mark Brown some rare action while it was Randolph to the rescue when he intervened to deny Sproule who had been set up after a run down the left wing by Paul Lawson.
The returning James McFadden came on for Motherwell just after the hour and cannoned a disappointing 22-yard free-kick against the wall.
County then proceeded to extend their lead when Brittain fired home Sproule's cross from the edge of the box.
This finally silenced a small but very noisy nucleus of Motherwell fans who had attracted the attention of two dozen police and stewards after half-a-dozen smoke bombs had filled the ground with pungent fumes.
Brittain next curled a free-kick narrowly by after Stefan Wolfarth had been body checked by McFadden and Vigurs prompted Randolph into another fine save.
However, Vigurs' next effort in the 89th minute was more successful when. From around eight yards, he smacked home a ball from the right to complete an emphatic victory.