John Hughes’ side are now unbeaten in eight games as goals from Greg Tansey and Ryan Christie sealed a deserved success as they moved level on points with second-placed Aberdeen.
St Mirren have now set a new club record for the longest run without a home league win after extending their run without a league victory in Paisley to 14 attempts.
Caley Thistle went in front after just three minutes as Graeme Shinnie teed up Tansey who fired first-time past ‘keeper Marc Ridgers
They continued to force the pace against a side which have yet to pocket a win bonus on their own ground this season, Gary Warren heading narrowly over the crossbar from a corner.
Moments later Marley Watkins scuttled clear down the inside left channel and drilled a low shot across the face of goal and two yards beyond the far post.
Warren again went close to doubling the lead with his head, this time rattling the goal frame as he rose highest at a corner.
David Raven embarked on a slaloming run down the flank before sliding the ball through to Ryan Christie (60) who produced a cultured left-foot finish.
Goodwin (68) pulled one back for Saints, crashing in a header from a corner, and the Saints’ talisman also threatened with a decently struck free-kick that flew narrowly wide. Marc McAusland headed wide late on but there was to be no reprieve for Gary Teale’s men.