Shane Sutherland, a product of the youth system at Inverness, and Alex MacDonald, on loan from Burnley, both scored their first goals for the club while captain Richie Foran was also on the scoresheet in this comprehensive victory.
The win moved Caley Thistle to within a point of Motherwell as the battle for a top-six place in the league intensifies, with the split fast approaching.
Inverness were first to get a shot on target, Foran laying the ball back into Russell Duncan’s path, but his low effort from 20 yards was saved down to his left by Darren Randolph in the visitors’ goal.
Foran was the creator again moments later, rising highest to head the ball down to the feet of Nick Ross, who failed to control when in plenty of space and the chance was lost.
Motherwell were having plenty of the ball in the early stages, but struggled to create anything in the final third and they soon found themselves trailing after 18 minutes.
Lee Cox picked out Sutherland on the right and he cut inside Steven Hammell before unleashing an unstoppable left-foot drive from 14 yards that crashed into the roof of Randolph’s goal.
Sutherland then came close to connecting with Foran’s cross, but his flick drifted a yard wide as Caley Thistle continued to be the more dominant force in the final third.
The Steelmen looked well off the pace, with their forward trio of Francis Jeffers, John Sutton and Jamie Murphy feeding on little more than scraps.
Aside from a couple of dangerous free-kicks by Ross Forbes, Motherwell failed to seriously test Ryan Esson in the home goal.
That all changed, however, with half-time approaching. Keith Lasley sent Sutton running through on goal, but Esson was out quickly to save at the forward’s feet.
Motherwell were finally beginning to offer a goal threat, Sutton again involved as he headed Forbes’ corner on to the roof of the net.
Both teams made lively starts to the second half, with Foran close to connecting with Duncan’s through-ball while at the other end, Jeffers was denied by Esson from Tom Hateley’s deep cross.
In an attempt to inject some attacking impetus into Motherwell’s play, manager Stuart McCall introduced Chris Humphrey into the action with the winger replacing Forbes.
Minutes later, Steven Saunders was brought on for Hateley as McCall shuffled his pack to try and find some way back into the contest.
Motherwell were showing more of an attacking intent, but they nearly came unstuck when a swift break by Inverness saw Ross go clear from a Cox pass only to fail to connect with the ball under pressure from Hammell.
The visitors failed to heed the warning and in the 64th minute they were left with a mountain to climb.
Ross sent Adam Rooney in on goal and the Irishman shaped as if to shoot, but instead crossed for Foran who fired the ball home from just inside the six-yard box with Randolph well beaten.
Motherwell’s response came courtesy of sub Humphrey, only for the wideman to first be thwarted by a wonderful save from Esson before Ross Tokely blocked his second effort on the line.
With the Steelmen committing more players forward, Cox had the chance to finish the game as a contest, but Randolph saved well at the midfielder’s feet.
Inverness boss Terry Butcher introduced MacDonald into the action and it was an inspired change as within 30 seconds of coming on he got his name on the scoresheet with 72 minutes gone.
Foran’s cross was misjudged by Gavin Gunning and the Scotland Under-21 international had the simplest of tasks to finish from close range.
Motherwell huffed and puffed in their bid to even score a consolation and despite Murphy having an effort pushed on to the crossbar by Esson late on, Caley Thistle comfortably held them at arm’s length to secure only their fourth league triumph at home this season.