Inverness won for the first time in four games and condemned Dunfermline to a third successive loss thanks to three unanswered second-half goals, Shaun Rooney, Liam Polworth and George Oakley on target as John Robertson’s side climbed up to second.
After an even opening 45, Caley Thistle went ahead in the 51st minute when Rooney got on the end of Tom Walsh’s cross to nod past Lee Robinson from close range.
As the Pars piled forward, they were caught out on the counter in the 71st minute.
Aaron Doran found Polworth at the back post and the midfielder slotted a first-time effort into the net.
Sub Oakley rubbed salt into Dunfermline’s wounds with a third in the 83rd minute with a cool finish after Doran flicked on goalkeeper Mark Ridgers’ kick out.
Robertson said: “We spoke to them about last year – we came away from this stadium having been battered 5-1 in the early weeks of the season and we were in disarray. We’re a year further on and we’re a team.”