Inverness powered to a convincing home win which maintained their unbeaten record against Aberdeen this season.
Johnny Hayes fired in several shots from distance for Aberdeen, but failed to trouble his former club's goal.
However, Andrew Shinnie beat Russell Anderson and rifled the ball into the top corner from a tight angle.
Then, a brace from Billy McKay - a low 12-yard shot and a left-footed strike into the roof of the net - put the match beyond Aberdeen.
Those goals lifted the Northern Irish striker's goal tally to 20 for the season.
Hayes, on his return to the Caledonian Stadium, came as close as anyone in the Aberdeen side to striking back but they could not break down the Inverness defence.
Aberdeen had the better of the early exchanges and after just two minutes Niall McGinn saw an effort tipped over for a corner by Antonio Reguero.
One of Caley Thistle's best chances of the first half followed soon after when Ross Draper nodded the ball on to Richie Foran whose own header was tipped away by Jamie Langfield.
Then Hayes entered the fray when he sent a 25-yard effort just over the bar before seeing another shot saved by Reguero.
Inverness next passed up another of the best opportunities of the first half when Graeme Shinnie squared the ball to McKay who could not quite make contact.
The second half had just started when Hayes was tormenting the Inverness back line again, eluding both Graeme Shinnie and Gary Warren, but Reguero responded in style to the Dubliner's shot at goal.
The breakthrough came in 54 minutes when Shinnie cut in from the left and beat Anderson to set himself up at an acute angle.
The Scottish international's contract talks may have stalled at Inverness but his appetite for goal certainly has not and he found the top corner from that tight position.
Then just after the hour, Inverness got an even stronger scent of victory when Draper supplied McKay whose low shot eluded Langfield for their second.
And with 12 minutes remaining, the game was in the bag when Andrew Shinnie was the supplier and McKay netted from 10 yards.