Match ends, Celtic 5, Kilmarnock 0.
Five teenagers started for Celtic as the League Cup holders swept aside Kilmarnock to reach the quarter-finals.
Leigh Griffiths scored either side of Anthony Ralston's first senior goal for the club to make it 3-0 at half-time.
Captain for the night Kieran Tierney netted a wonderful strike from distance that will long live in his memory and the fans who witnessed it.
Stuart Armstrong tapped in to cap a straightforward night for Celtic and a sore one for Kilmarnock.
It was not a birthday to remember for Kilmarnock's Kirk Broadfoot as he and Gordon Greer looked to forge their new central defensive partnership in testing circumstances.
Only Craig Gordon, Tierney and Griffiths continued with starting berths from the Celtic 11 that began the weekend's 4-1 Premiership victory over Hearts.
Manager Brendan Rodgers offered more first-team experience to Ralston (18), left-wing-back Calvin Miller (19) and recent signing from Ipswich Town Kundai Benyu (19).
Kristoffer Ajer (19) and Eboue Kouassi (19) were the others under the age of 20 handed the responsibility of helping Celtic get off to a smooth start in defending one part of the domestic treble they captured last season.
Tierney was deployed as a centre-back beside Ajer, who spent much of the 2016-17 campaign on loan at Kilmarnock, but the home defence had little to do.
Not so at the other end, and a silly foul from winger Jordan Jones on Jonny Hayes handed the hosts an early penalty that Griffiths fired into the bottom corner.
A memorable moment for Ralston soon followed when he headed in Griffiths' corner kick after being given too much space by the Killie defence.
Goalkeeper Jamie MacDonald could not stop that one but he did well to beat away a stinging effort from Griffiths and he went on to make an even better stop from Armstrong later.
The visitors had started Lee Erwin up front in place of Kris Boyd but the ball rarely made its way that far up the pitch as Killie were pinned back.
Tierney highlighted his ever-increasing skill-set in many ways in this match. Playing as captain and centre-back was only the beginning, as he impressed with a nice threaded pass to set up Griffiths for his fourth goal in two games - the striker springing a half-hearted Killie offside trap before calmly slotting in to give his team a 3-0 lead at the break.
Tierney then sent a 40-yard screamer high into the top corner for Celtic's fourth. It was a terrific strike that the man, already capped four times for Scotland, will struggle to better in what promises to be a bright future.
The busy Hayes scampered down the right for his second assist of the night, sending an inviting low cross for Armstrong to side-foot home from close-range.
One negative for Celtic was a nasty looking injury for Kouassi, who was taken off after jarring what looked like his knee or ankle.
- 88KouassiSubstituted forNtchamat 40'minutes
- 26BenyuSubstituted forMcGregorat 70'minutes
- 9GriffithsSubstituted forForrestat 64'minutes
- 24de Vries
- 20WilsonSubstituted forO'Donnellat 59'minutes
- 7McKenzieBooked at 61mins
- 11JonesSubstituted forGrahamat 45'minutes
- Alan Muir
- Shots on Target
Second Half ends, Celtic 5, Kilmarnock 0.
Attempt missed. Kristoffer Ajer (Celtic) header from the centre of the box is high and wide to the right following a corner.
Corner, Celtic. Conceded by Jamie MacDonald.
Attempt saved. Tomas Rogic (Celtic) right footed shot from the centre of the box is saved in the top left corner.
James Forrest (Celtic) wins a free kick on the right wing.
Foul by Gordon Greer (Kilmarnock).
Attempt blocked. Chris Burke (Kilmarnock) left footed shot from outside the box is blocked.
Delay in match James Forrest (Celtic) because of an injury.
Attempt blocked. Rory McKenzie (Kilmarnock) right footed shot from outside the box is blocked.
Attempt saved. Stuart Armstrong (Celtic) right footed shot from outside the box is saved in the centre of the goal.
Attempt blocked. James Forrest (Celtic) right footed shot from the centre of the box is blocked.
Attempt missed. Tomas Rogic (Celtic) left footed shot from outside the box is just a bit too high.
Attempt blocked. Stuart Armstrong (Celtic) right footed shot from outside the box is blocked.
Callum McGregor (Celtic) wins a free kick in the attacking half.
Foul by William Graham (Kilmarnock).
Tomas Rogic (Celtic) wins a free kick in the defensive half.
Foul by Alan Power (Kilmarnock).
Goal! Celtic 5, Kilmarnock 0. Stuart Armstrong (Celtic) left footed shot from very close range to the bottom left corner. Assisted by Anthony Ralston.
Substitution, Celtic. Callum McGregor replaces Kundai Benyu.