Ross County moved second in Scottish Football League Division One after thrashing Ayr United, who slip to the bottom of the table.
Richard Brittain's left-foot shot put the hosts ahead after five minutes.
The home fans had to wait until the 64th minute for the second goal, Paul Lawson finishing well.
Sammy Morrow soon fired home from the edge of the box and Iain Vigurs completed the scoring three minutes from the end with a close-range effort.
Ross County: Fraser, Miller, Boyd, Munro, Fitzpatrick, Vigurs, Brittain, Lawson (Duncan 83), Quinn (Byrne 75), Morrow (Corcoran 69), McMenamin. Subs Not Used: Malin, Flynn. Booked: Vigurs, Byrne.
Goals: Brittain 5, Lawson 64, Morrow 69, Vigurs 87.
Ayr: Cuthbert, Tiffoney, Smith, Ross Robertson, Malone,Moffat, Geggan, McKernan (Wardlaw 67), McGowan (Connolly 81), Trouten, Roberts. Subs Not Used: McWilliams, Burke, Armstrong.
Booked: McKernan, Trouten.
Ref: Gary Hilland