CALEY Thistle made sure there was no Irn-Bru Cup shock in Inverness as they beat League Two visitors Peterhead 3-0 to book their last eight spot.
Goals from Liam Polworth, Ricky Calder and 16-year-old sub Daniel Mackay on his debut put John Robertson's Championship strugglers into Tuesday's draw.
ICT went into this one on the back of a goalless draw against Queen of the South and made two changes.
Calder and Joe Chalmers were handed starts, with striker George Oakley dropping to the bench and midfielder Charlie Trafford suspended following his red card against Aberdeen under-20s in the previous round.
The Blue Toon also made two changes from the team which slipped to a 2-0 home loss against Berwick Rangers last week.
Skipper David McCracken came in for Mason Robertson and Russell McLean replaced Allan Smith.
The tone of the tie was set after just 90 seconds when Polworth picked up play just outside the box and his deflected drive flew beyond goalkeeper Greg Fleming into the left side of the net.
What a start for a team low in confidence and self-belief.
Peterhead came into the game though and former Caley Thistle forward Rory McAllister saw his overhead kick fly over the bar then Jamie Stevenson went close.
There was no real golden moments for the remainder of the first half and ICT were happy to be in control.
The killer second goal arrived just six minutes into the second half when classy Calder played a one-two with Polworth before guiding the ball past Fleming into the net.
It was a terrific goal and seemed, for a while, to knock the stuffing out of Jim McInally's team.
The main talking point for Robertson afterwards was the goal for teenager Mackay, who will be one of the club's youngest scorers.
After replacing Calder in the final minute, he went close before netting a follow-up to a shot from fellow sub George Oakley.
What a terrific moment on the young kid's debut and he enjoyed the celebrations with his equally thrilled Caley Jags team-mates.
Meanwhile, it emerged after the game that Polworth and coach Scott Kellacher were involved in an angry bust-up when the player was subbed as tempers boiled over.
Caley Thistle will now look to build on this victory when they resume their battle to move up from second bottom spot in the Championship on Saturday with a trip to Falkirk, who last week made Paul Hartley their new boss.
Then follows a trip to title favourites Dundee United and a home date with Dunfermline Athletic.
Inverness CT: Fon Williams, Raven, Mckay, Chalmers, Donaldson, Tremarco, Vigurs, Polworth (Cooper 86), Calder (Daniel Mackay 89), Bell (Oakley 76), Baird. Subs not used: Ridgers (GK), Elsdon, Brown.
Peterhead: Fleming, Stevenson, Jason Brown, McCracken, Macilduf, Gibson, Ferry, Scott Brown (Lawrence 86), Leitch, McLean, (Smith 55) McAllister 6 (Adams 76). Subs not used: Hobday (GK), Robertson, Dikobo, Gabriel.
Referee: Alan Muir.