A Barry Lawson goal eight minutes after half-time was enough to secure a 1-0 victory for league leaders Livingston at Ross County.
Lawson's shot from just inside the 18-yard box was deflected past County 'keeper Garry Hamilton to earn title-chasing Livvy all three points.
Davide Sausa almost put the league leaders in front in the fourth minute when his shot rebounded off the underside of the crossbar.
County's first effort of note came after 17 minutes when Ian McColgan got down well to stop a fierce Hugh Robertson drive.
Javier Vroto replaced McColgan at the start of the second half and he was soon in action blocking McQuaid's goalbound shot.
But it was Livvy who took the lead five minutes later when Barry Lawson fired home the winner from 16 yards.
County tried hard to get back on level terms and Alex Bone, Martin Prest and Kerim Boukraa all came close for the home side, but they could not force an equaliser.