Caley Thistle, who make their European debut with a Europa League tie against Astra next Thursday, stormed into a 4-0 lead at half-time with two goals from Greg Tansey and one apiece from Aaron Doran and Lewis Horner.
Doran left the field after the break and Inverness were forced to play with only 10 men for much of the second half as they had already used all seven outfield substitutes but that did not prevent them from adding a fifth goal through a triallist.
Meanwhile, Motherwell fielded two triallists as they drew 1-1 with Borussia Monchengladbach U23s in their opening pre-season friendly at Rheden in the Netherlands, one of whom was believed to be 21-year-old Leicester defender Kieran Kennedy.
Former York striker Wes Fletcher opened the scoring in the 49th minute when he was hand to net from close range after Craig Moore’s shot had been spilled by the German side’s ‘keeper.
Giuseppe Pisano levelled in the 70th minute following an impressive solo run and Motherwell goalkeeper Brett Long then made a superb save to deny Nils Rutten.
Motherwell could also have won it late on but Ross MacLean curled his shot inches wide with the goal at his mercy.
Second-half goals from Gary Oliver and Jamie Walker handed Hearts a 2-0 victory over Raith Rovers in Kirkcaldy.
Summer signing Blazej Augustyn captained Hearts, who made 10 substitutions on the hour mark as they made it three wins out of three games so far in pre-season.