A close contest had been expected but the 19 points separating the teams by full-time seemed like a fair reflection of the difference in their respective performances, and goals from David Raven, Billy McKay and Marley Watkins seemed like a just return for the visitors.
County's key players failed to perform to expected standards, while John Hughes' team, to a man, looked ravenous for revenge from the first whistle. Their win ended a run of Dingwall disappointments for Inverness who climbed back to fourth place in the SPFL Premiership table, above Dundee United.
County, who slipped back to 10th place on goal difference, had not lost one of these contests at home to their great rivals for nearly a decade. To put that in context, Tony Blair was still clinging on to mild popularity in 10 Downing Street at the time.
But Inverness have held overall sway in encounters with their neighbours, and it must have irked them to have been beaten in both of the most recent two before last night.
Adams sprang a minor surprise by recalling Alex Cooper in place of Graham Carey in his only change from last Saturday's 2-1 win over St Mirren. Notably, though, Cooper had netted in the New Year's Day victory. Hughes, likewise, made a single change after victory at St Johnstone, with James Vincent preferred to Watkins.
Inverness opened the scoring with their first serious attack, after eight minutes. From Vincent's pass down the left, Aaron Doran's explosive turn of pace left Brian McLean for dead and the Irishman cut the ball back for Raven who just managed to squeeze it inside the post despite the attentions of Evangelos Oikonomou a few yards out with just enough force. It was right-back Raven's first goal for Inverness after more than 60 appearances.
After 24 minutes, County had penalty claims waved away when Jordan Slew's strike hit defender Gary Warren on the hand. The visitors broke immediately, with Graeme Shinnie slicing past Richard Brittain from the left, then going for glory. Only the slenderest of fingertip saves down low from Mark Brown spared County.
Shinnie was impressing and it was his sharpness in stealing the ball from Slew 30 yards out that led to Caley Thistle's second goal five minutes from the break.
The left-back instinctively knew where Billy McKay would be and whipped it across for the club's top scorer to net with a sweet first-time finish from 12 yards. It was McKay's 20th of the season after three games without a goal.
There was hope for County early in the second half when Cooper's ball dragged across the box was met on the volley by Michael Tidser but Dean Brill, the Inverness goalkeeper produced a tremendous reflex save to push the powerful strike over his bar. The frantic pace continued with Filip Kiss sending another attempt spinning just wide of Brill's goal.
At the other end, McKay released Doran clean through the middle with a long, pin-point pass but full-back Erick Cikos made a tremendous recovering tackle in the box.
County made substitutions, desperate to spark something better, with Carey and Saturday's matchwinner Melvin De Leeuw introduced. However, entering the final quarter of the match, the Dingwall team were labouring in terms of creativity.
Slew has a sight of goal from inside the Caley Thistle box but could only turn and strike into Brill's arms.
Inverness thought they had won a penalty when Doran tumbled in the box under a challenge by Cikos, but referee Calum Murray gave a goal kick. However, the match was all over bar the shouting after 78 minutes.
Again, it was the excellent Doran who created the opening with a skilful, perfect flick into the path of substitute Watkins, who strode into the box on the right and calmly powered a shot into the far corner.
After the final whistle, Hughes, a veteran of Old Firm and Edinburgh derbies, spoke in glowing terms of the Highland version and expressed a hope that County will avoid play-off danger to remain in the top flight next season. "This was a breath of fresh air to me here tonight," he said. "I know it is easy to say that when you win but this derby is played in a great spirit and the fans are absolutely different class. We've just seen a derby match abroad where a supporter was killed by other fans. I've been in derby matches and some of it is not nice. This is absolutely fantastic to be part of."
Adams was magnanimous in defeat, although clearly bitterly disappointed. "Take nothing away from Inverness, I thought they were excellent," he said. "We've lost three bad goals and weren't able to get back into the game after the first one.
"Inverness were stronger and capitalised on our mistakes, while offensively we didn't do enough. We probably have a younger side than they do and less experience in derby matches - and that showed."