Logan Chalmers got Thistle's second goal in Dingwall
Partick Thistle won a Scottish Championship game for the first time this season to leave Ross County bottom of the table.
Ben Stanway struck to put Thistle into a first-half lead and Logan Chalmers turned in the visitors' second soon after the break.
Connor Randall reduced County's deficit from inside the box.
However, Steven Lawless made sure of the points for Partick with a spot-kick in added time, awarded after Alex Iacovitti was penalised for handball.
