Caley Thistle’s three-match winning run in the Championship was brought to a halt by Partick Thistle at Firhill Stadium.
Goals from Alex Jones, Steven Saunders and Dario Zanatta settled a thrilling end-to-end encounter at Firhill Stadium in the home side’s favour.
James Keatings had equalised for the Highlanders.
Caley Thistle boss John Robertson named the same starting line-up which beat Ayr United 2-0 the previous weekend.
Both sides contributed to an entertaining opening and the only surprise was that neither team was rewarded with a goal.
Miles Storey went close for Caley Jags in the opening 10 minutes while visiting goalkeeper Mark Ridgers saved twice from Reece Cole.
Inverness also had a penalty claim turned down when Jordan White went down under a challenge from Tam O’Ware but referee Steven McLean booked the Caley Jags striker.
Manager Robertson also joined his player in being cautioned following his protest against the decision.
Shaun Rooney tested Scott Fox at the start of the second half as Inverness continued to push for an opener but it was the home side which broke the deadlock when Alex Jones ran clear to fire past Ridgers.
Inverness were not behind for long, however, as from a corner James Keatings hooked the ball over his shoulder into the net to make it 1-1.
Partick were back in front by the 65th minute as they scored again from a corner of their own.
Cole’s delivery was met by Kenny Miller and with the Inverness defence failing to clear their lines Steven Saunders fired low past Ridgers to make it 2-1.
Inverness committed men forward in search of an equaliser and they were caught on the break in injury time as substitute Gary Harkins sent Zanatta clear on goal and he fired home from a tight angle to secure victory.