Caley Thistle produced an excellent backs to the wall performance to secure all three points at St Mirren after playing for 40 minutes with 10 men.
A Greg Tansey penalty proved the difference between the sides at St Mirren Park but Inverness deserve great credit for grinding out the win after Ryan Christie was sent off in the 50th minute.
Inverness manager John Hughes made one change to the side which drew 1-1 with Ross County in the Highland derby with Danny Williams starting in place of Aaron Doran, who was named among the substitutes.
New signing Ibria Sekajja was also named on the bench after signing for the club during the international break.
Caley Jags had the ball in the back of the net with their first attack in the 15th minute when Graeme Shinnie’s cross was converted by Billy Mckay but his celebrations were cut short as his effort was chalked off for offside.
Despite playing against a strong wind in the first half it was the visitors who created the better chances but they had to wait until just before half-time to make the breakthrough.
Defender Gary Warren was hauled to the ground by Saints captain Marc McAusland as he went to contest a free kick and referee Willie Collum pointed to the spot.
Greg Tansey converted the penalty, firing low to Marian Kello’s left.
Caley Thistle’s joy at taking the lead was shortlived, however, as they found themselves reduced to 10 men five minutes into the second half when Ryan Chrisite, who had been booked in the first half, was sent off for a foul on Saints midfielder John McGinn.
But Caley Jags dug deep to claim the win and Billy Mckay was unlucky not to score a second late in the game but Kello blocked his close range effort.