Caley Thistle dropped to ninth in the Championship after a 1-0 home defeat against Greenock Morton.
Aidan Nesbitt grabbed the game’s only goal 11 minutes into the second half.
The defeat left Neil McCann’s side with just one win in 12 games and in the Championship’s relegation play-off spot.
Morton moved up three places to sixth after ending a 10-game run without a win.
Home caretaker manager Neil McCann brought back Danny Devine, Scott Allardice and James Keatings into his starting line-up after a frustrating draw away to Alloa on Saturday.
Cameron Harper and Miles Storey were missing, presumed injured, while skipper Sean Welsh was part-rested on the bench amid the busy spell of matches.
Morton took a surprise lead after 56 minutes after great link-up play from Craig McGuffie and Luca Colville ended with the latter cutting a low pass to the right side of the home penalty area where Nesbitt showed control and poise to beat Mark Ridgers with a fine low finish into the left hand corner of the net.
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Morton only grew in confidence with a lead to defend and the game became bogged down in broken play and stoppages as the hosts tried to regain a foothold.
Ton defender Markus Fjortoft almost grabbed a second with 12 minutes remaining as he powered a header just over the bar from a corner.
It was an all-out Inverness assault towards the close with Shane Sutherland’s snapshot from the edge of the box saved low by Aidan McAdams.
Nikolay Todorov had the ball in the net almost on full time, on the rebound after Sutherland hit the bar, but it was ruled offside and only served to sum up their night.