Caley Thistle dropped to third the Championship after rock-bottom Dunfermline Athletic’s 2-1 victory earned the visitors their first win of the season.
It’s now five matches without a win for Inverness as they have been overtaken by Raith Rovers and stand four points adrift of leaders Kilmarnock.
ICT head coach Billy Dodds was understood to be absent due to illness and his players let a lead slip for a second successive home defeat on the back of losing to Arbroath here recently.
Billy Mckay tucked away his seventh of the season, his second league goal so far, to put the Highland team in front midway through the first half.
The game was turned on its head in the second half.
An unfortunate Danny Devine own goal just after the break made it all square the a sublime Dom Thomas goal fired the rock-bottom Pars towards all three points.
This result, which was their first away league win in over a year, hauls them to within two points of Queen of the South and Morton.
On Friday, the Fifers unveiled ex-ICT and Ross County manager John Hughes as their new boss, replacing Peter Grant, who was recently sacked after just 156 days in charge.
Although Hughes was here in Inverness, the team was for the second week running taken by caretakers Steven Whittaker and Greg Shields.
Caley Thistle were on a mini-slump by their high, early-season standards, but began the day just one point behind leaders Killie after ICT’s 2-2 draw at Ayr United last week.
Carson returns to right-back berth
The only changes from the hosts following their draw in Ayr were the return of right-back David Carson for Wallace Duffy and Reece McAlear coming in for skipper Sean Welsh.
The Pars made three changes to the team which slumped to a 3-1 loss against Morton.
In came Kyle MacDonald, Lewis McCann and captain Graham Dorrans were starters.
Kai Kennedy is on international duty so was absent, while Paul Allan and Ryan Dow began the day on the bench.
The first chance of the contest fell to Inverness as Aaron Doran’s stinging effort brought a fine diving save from former ICT keeper Owain Fon Williams.
Mckay was next to have a go, but his looping effort had too much height to trouble the Welshman.
Striker Mckay breaks the deadlock
Mckay was not denied on 22 minutes, however, as he was ideally placed to slot away a close-range shot after Michael Gardyne’s swerving 25-yarder came off the post and into his path.
The Pars were not offering much and a Thomas free-kick sent into the box on the half hour mark was mopped up with ease to their frustration.
They came closer a few moments later though when, from a Thomas corner, ICT keeper Mark Ridgers was required to block a net-bound Rhys Breen shot then Mark Connolly’s effort was blocked by Danny Devine.
Ridgers got down to save another shot on 40 minutes, this time from Josh Edwards as Dunfermline grew into the game.
Pars at the double in the second half
Six minutes into the second half, the travelling fans were on feet and signing ‘We’re Going To Win the League’ when Devine turned the ball past Ridgers when trying to stop Lewis McCann connecting with an Aaron Comrie cross.
It was a crushing blow to ICT and they needed a reaction, especially with Killie winning at Morton.
Matters worsened on 64 minutes when in-form Thomas gathered the ball, worked into the box and curled an inch-perfect shot into the top corner.
McAlear almost levelled moments later, but there was annoyance in the stand as ICT struggled to find a spark.
Scott Allardice drilled a low shot off target and Doran missed with a header as the Caley Jags pressed late on, but it was not to be.
Inverness are back on the road next week as they travel to Dumfries to take on Queen of the South on Friday. Dunfermline welcome Ayr to East End Park on Saturday.
CALEY THISTLE (4-4-2): Ridgers 6, Deas 6, Devine 6, Gardyne 6, Carson 6 (McDonald 80), Mckay 6, Doran 6, Walsh 6 (MacGregor 67), Broadfoot 6, Allardice 6, McAlear 6 (Jamieson 67). Subs not used: MacKay (GK), Harper.
DUNFERMLINE ATHLETIC (4-4-2): Fon Williams 6, Comrie 6, Edwards 6, MacDonald 6, O’Hara 6, Breen 6 (Graham 73), McCann 6 (Dow 84), Dorrans 6, Thomas 7, Todd 6 (Pybus 61), Connolly 6. Subs not used: Mehmet (GK), Wighton, Todorov, Allan.
Referee: Grant Irvine.
Attendance: 2111.
Man of the match: Dom Thomas.