Injury-hit Caley Thistle are now nine points off top spot in the Championship after falling to a 1-0 home loss against promotion rivals Dundee.
Paul McMullan’s searing first-half goal made all the difference, which stretched ICT’s winless run to seven league matches.
Amazingly, this was the Taysiders’ first league victory at the Caledonian Stadium.
Ayr United’s 2-0 victory over Raith Rovers means the north side are three wins away from first position and six points away from the top four.
For Dundee, it places them just one point away from Ayr, to the delight of their sizable, vocal travelling support.
Inverness, who won 3-2 at Dundee in September, are missing nine players through injury as they sought to win their first league game since leaving Cove Rangers as 1-0 victors in mid-October.
A hard-earned 3-2 home victory against League Two opponents Stirling Albion in the Scottish Cup last week put them into a fourth-round crack at Championship foes Queen’s Park on January 21.
Striker Billy Mckay missed out with a calf strain, so George Oakley replaced him, with on-loan Hibs winger Dan MacKay came in for Scott Boyd.
The Taysiders, who last lost in the league at the start of October, were riding on the crest of a wave, and on the coat-tails of pace-setters Ayr United.
Their consistent form earned Gary Bowyer and Paul McMullan the respective latest manager and player of the month prizes for November.
They went into this game on the back of a 6-2 extra-time win over Airdrie in the Scottish Cup, which earned them a trip to Premiership hosts St Mirren.
Dundee made two changes from last week’s cup-tie, with goalkeeper Adam Legzdins and defender Tyler French replacing Ian Lawlor and Max Anderson.
McMullan shot beats keeper MacKay
Winger Nathan Shaw carved open the first chance for the hosts as he fired in a telling cross. It broke out to David Carson and rifled a shot wide of the left post.
Dundee were neat and tidy, but not finding a way through.
Danny Devine then showed urgency on 13 minutes as he burst forward and fed the ball to Aaron Doran and flashed a low drive beyond the left post.
However, the opener came on 26 minutes when November’s Championship player of the month McMullan collected a pass from Ben Williamson on the left flank and guided a terrific angled 25-yarder beyond goalkeeper Cammy MacKay into the net.
Just before the interval, the Dark Blues tested Cammy MacKay once more when Cammy Kerr moved inwards and his shot was beaten away by the goalkeeper.
There was time for one more chance before half-time as ICT attacked, but French was on hand to clear away from the lurking Oakley at the key moment.
Doran dipper gives Inverness hope
The second half contained plenty of work-rate all over the pitch, but the first chance of note arrived on 64 minutes with a dipping drive from Aaron Doran which just cleared the crossbar.
Match-winner McMullan went on a Maradona-like run, but the move ended when Josh Mulligan failed to control the ball when he was picked out.
A range of changes from the bench in the closing period didn’t deliver a killer goal for Dundee or a leveller for Caley Thistle.
Luke McCowan came closest to finding the net when the visiting sub forced a save from Cammy MacKay just before Mulligan also tested the goalkeeper.
Caley Thistle’s Oakley stabbed an effort late on and Dan MacKay flashed a low shot too far wide, but it had Legzdins watching it closely.
It’s SPFL Trust Trophy time for ICT next weekend as they visit Hamilton, seven days before return there on league business.
CALEY THISTLE (4-4-1-1) – Cammy Mackay 6, Duffy 6, Harper 7, Devine 6, Carson 7, Doran 7 (Nicolson 84), Oakley 6, Ram 6 (Barrett 72), Hyde 6 (Boyd 72), Dan MacKay 7, Shaw 6. Subs not used – Ridgers (GK), Boyd, Strachan, Calum MacKay, Bray.
DUNDEE (4-3-3) – Legzdins 6, Kerr 7, French 7 (Grayson 90), Sweeney 6, McGhee , Byrne 6 (Robertson 70), Ashcroft 6, Mulligan 6, McMullan 7, Rudden 6 (McCowan 7), Williamson 6 (Osei 70). Subs not used – Sharp (GK), Jakubiak, , Sheridan, Anderson , Cameron.
Referee – Alan Muir.
Attendance – 2435.
Man of the match – Danny Devine.
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