The East End of Glasgow will host the finals of both of Scotland's cup competitions this season, but Neil Lennon's side will be on the outside looking in.
Defeat to Aberdeen yesterday means they have exited both competitions before the quarter-final stage for the first time since 1982. The link to that decade was appropriate, because with Aberdeen proving their mettle in Glasgow, at times this felt like a bit like an 80s revival.
Last weekend a segment of the Aberdeen support had thrown plastic cups and a coin at the Northern Irishman; yesterday the onslaught from the stands was merely verbal. But events on the field were another wounding blow to the prestige of a manager who might have reigned supreme in the league but who has lifted just two of the seven domestic cups he has contested. "We have to show a bit of character," said Lennon, concerned now that his season may peter out. "We all have to take the criticism - the players, myself - and we have to finish the season really well with a view to going into next season."
When the final whistle sounded the travelling support of some 3000 from the north-east utterly gloried in it all. This was, after all, their first win here since another cup triumph under Jimmy Calderwood in 2008, an oasis amid a desert of 17 successive league defeats at this venue.
Aberdeen joined the dwindling band of SPFL Premiership sides in today's quarter-final draw, with a return journey to this stadium next month already booked against Inverness Caledonian Thistle in the League Cup final. It also means a second season will pass without an Old Firm match.
Lennon's scouting last week hadn't entirely been in vain, with the Pittodrie side keeping the XI which routed St Johnstone in last week's League Cup semi-final. Celtic made two changes, introducing Adam Matthews and Georgios Samaras for Darnell Fisher and Charlie Mulgrew, with Anthony Stokes given the nod up front ahead of new boy Leigh Griffiths.
The Irishman, one of his side's better players on the day -perhaps impressing the watching Republic of Ireland assistant boss Roy Keane - largely vindicated that decision, not least when he opened the scoring after eight minutes. Samaras conjured an imaginative pass and Stokes killed it instantly before sending in a finish which Jamie Langfield could only help into the net.
With Fraser Forster going into the match chasing Charlie Shaw's century-old record of 13 consecutive clean sheets in domestic matches, such a start might have disheartened some teams, but it takes more than that to throw this Aberdeen side off their stride. With Efe Ambrose ill-at-ease dealing with the thrusts of Adam Rooney, and deeper midfielders Barry Robson and Willo Flood keeping Kris Commons at bay, they held plenty of possession and started wielding menace from set-pieces specifically designed to unpick Celtic's zonal marking system.
One Robson corner from the left, headed down by Andrew Considine and flicked on by Jonny Hayes, had struck the Celtic bar before Considine chested down another, and Russell Anderson acrobatically directed it into the net from close range after 38 minutes. Forster's clean sheet clock - it doesn't, of course, include the six conceded at Barcelona's Camp Nou - stopped at 1062 minutes.
If conceding one goal was unusual for the Parkhead side, losing a second in such short order was distinctly careless. A clever Robson pass just minutes into the second period fed Peter Pawlett and he shot, left footed, across Forster's body and in off a post. The other post wasn't quite so friendly to Pawlett soon afterwards, however, as he struck it following a lightning quick break involving Niall McGinn and Rooney.
The scorer was unable to complete the match due to a head knock, but unlike the 3-1 win here earlier this season there was to be no late salvation for Celtic. Griffiths duly entered the fray and showed a few nice touches, but his only effort on goal was tugged wide of a post, while the clearest chance was headed on to the roof of the net by Virgil van Dijk.
Suffice to say Derek McInnes wasn't counting his chickens about a double just yet. "Inverness will have the same aspirations as us in the League Cup final," the Aberdeen manager said, "And there will be seven other teams in the Scottish Cup draw who will be thinking the same as us."
Unsuprisingly, the fans weren't quite so circumspect. "Bring on the Rangers," they chanted.