Both sides had a settled look about them as neither made changes from the previous week.
The early stages were dominated by the visitors as Graham Bayne and Richard Hart both had efforts without really troubling keeper Gordon Marshall.
It was therefore no surprise when Inverness opened the scoring after 17 minutes.
A long ball reached the head of Marc Fitzpatrick but he could only lay the ball into the path of Hart who hit a crisp first time shot low under Marshall.
Three minutes later Hart almost proved provider when his cross was met at the edge of the box by Roy McBain but the midfielder's shot was wild.
It took until the 31st minute for the home side to have any kind of effort on goal – Martyn Corrigan's deep cross was headed back across goal by David Clarkson and Richie Foran could only steer the ball over the bar.
The first half was error strewn for the home side and they showed no semblance of the style that had taken them to five straight league victories.
It was another error that was to see them move two goals down. Ross Tokley's cross saw Marshall and Stephen Craigan get in a tangle leaving Bayne an inviting open goal to hammer the ball into.
The home side almost fell further behind at the start of the second half when another error on the edge of the box released Hart but Marshall stood up well to save at the expense of a corner.
The Well were struggling to find a way back into the game summed up by Scott Leitch's shot from the edge of the box which cleared the bar by a distance. But after 65 minutes they did get a goal back thanks in part to another error.
Foran turned Darren Dods on the edge of the box and visiting keeper Mark Brown could only fumble the ball into the path of Clarkson who blasted the ball home from close range.
Motherwell looked to have won a penalty with ten minutes to go when Brown appeared to haul down Clarkson. The ref thought differently and showed a yellow to the young striker for diving.
Following the booking Clarkson took his protest too far and was shown a second yellow and then the red.
Despite a couple of late corners the home side could not find an equaliser and their fine run came to an end, whereas the visitors registered their first win under new boss Brewster.