Caley Thistle fell to a 2-0 Championship defeat against Alloa Athletic at Recreation Park.
The Wasps were good value for their victory, which came through first half goals from Lee Connelly and Alan Trouten.
The result is Alloa’s first victory in six meetings with Inverness this term, with the Highlanders’ lead in second place over Ayr United cut to two points.
Inverness made two changes from the side which struck late to defeat Morton 3-2 on Tuesday, with Brad Mckay returning from suspension and Aaron Doran also drafted in, with Kevin McHattie and Roddy MacGregor dropping to the bench.
Inverness were forced to make a further change after just a minute when Lewis Toshney pulled up injured, prompting a quick recall for McHattie.
The Wasps took the lead on 12 minutes, when Scott Banks’ delivery from the right picked out Connelly, with his angled effort taking a hefty deflection off Mckay to leave Mark Ridgers helpless.
Inverness had a glorious opportunity to equalise on 21 minutes, with Jordan White knocking Charlie Trafford’s header towards goal from point-blank range, only to be denied by an excellent reaction save from Neil Parry.
The hosts doubled their advantage just before the half-hour mark, with Connelly’s free-kick finding the unmarked Trouten at the far post, allowing the midfielder to guide an effort past Ridgers.
Caley Jags saw efforts from Shaun Rooney and Mckay thwarted by Parry before the interval, however the Wasps came close to a third goal early in the second half when Banks saw an effort beaten away by Ridgers.
It was the Wasps who continue to pose the greater second half goal threat, with Trouten hitting the post from a tight angle on 64 minutes after Ridgers had parried Connelly’s low effort.
Inverness looked to pull one back, with White nodding over the bar from Tom Walsh’s cross before seeing another header comfortably saved by Parry shortly afterwards.
Alloa continued to look dangerous, with the impressive Banks sending an effort narrowly over following a superb mazy run.
Walsh saw an angled drive narrowly brush the crossbar on its way over, while at the other end substitute Adam Brown struck the post with a low effort in the dying stages.