SCOTTISH CUP/Fifth Round - Inverness ... 1 Celtic ... 0: UEFA Cup semi-finalists they may be, but Celtic found domestic affairs much less to their liking as Inverness Caledonian Thistle did to them what Liverpool had so miserably failed to do on Thursday night.
In a remarkable repeat of the victory over their illustrious opponents of three years ago, the first division team enjoyed another dramatic Scottish Cup triumph.
Then it was 3-1 at Parkhead, this time 1-0 at their own neat Caledonian Stadium to earn themselves a semi-final against either Falkirk or Dundee.
A wonderfully executed goal from Dennis Wyness on the stroke of half-time was all that separated the sides.
This was a greater cup upset than even the previous one, for then Celtic were in disarray and Caley's victory spelled the end of John Barnes's tenure as Parkhead manager.
This time, they met a Celtic team fresh from that fine European win at Anfield, although the team sent out by manager Martin O'Neill to maintain their Scottish Cup hopes was unrecognisable from the one that did so well on Merseyside.
An ecstatic Caley manager John Robertson could not hide his delight or pride in his players.
"It's been a phenomenal night. We needed every one of our players to play well and for Celtic not to be firing on all cylinders plus a little bit of luck. All that happened.
"People here are in a state of shock right now and it's all very hard to take in. My nerves, for instance, are gone and it will take a bit of time to realise we have done something special."
Goalkeeper Mark Brown, formerly of Rangers, savoured the moment as man of the match. "I don't know if it can get any better than this and it is the highlight of my career. We knew Celtic had had four hard games recently and we decided to have a go."
At least O'Neill won't suffer the same fate as Barnes endured.
"I have to take all the responsibility," he said. "There are no excuses. We didn't play well in the first half and all credit to Caley.
"It is very, very disappointing because I never want to lose any game and to come from the euphoria of Liverpool to this is hard to take."
INVERNESS CT: Brown, McCaffray, Mann, Munro, Golabek, Tokely, Hart, McBain, Robson (Christie 85), Wyness, Ritchie (Keogh 81). Subs Not Used: Stewart, Bagan, Fraser. Booked: Hart. Goals: Wyness 45.
CELTIC: Broto, Valgaeren, Varga, Laursen, Smith, Lennon, McNamara, Fernandez, Guppy, Maloney (Hartson 63), Larsson. Subs Not Used: Douglas, Balde, Healy, Miller. Booked: McNamara, Lennon.
Referee: A Freeland (Aberdeen).