Celtic's Champions League adventure began with a huge win, but Brendan Rodgers' side were brought back down to earth with a bang after a 7-1 thrashing at Borussia Dortmund.
The Hoops arrived at Signal Iduna Park in an optimistic mood and in free-scoring form after 17 consecutive wins, including that 5-1 victory over Slovan Bratislava in their opening match.
However, as they went toe-to-toe with the German side, mistakes were punished and Rodgers' side were on the end of the kind of thrashing they have been handing out themselves in recent weeks.
After another forgettable night on the biggest stage, does the Celtic manager need to change his approach against Europe's elite?
It is the third time Rodgers has conceded seven goals in a Champions League game - following defeats to Barcelona and PSG - while the Hoops were also hit for six last season by Atletico
Former Celtic player and Sky Sports pundit Chris Sutton believes Rodgers got his tactics wrong.
In a post on X, he said: "Celtic wanted to go toe to toe, [it is] good to be positive but there comes a time when you have to be a bit streetwise and understand levels.
"Throwing lots of bodies forward when you're 7-1 down seemed a bit naive - a bit like Madrid - way too open and ruthlessly exploited."
Rodgers always insisted he returned to help Celtic not only dominate domestically but also make a "breakthrough" in the Champions League.
Last season was a tough learning curve. While they won their first home group-stage game in 10 years - beating Feyenoord - they last won on the road in 2017, during Rodgers' first spell at the club.
The defeat in Dortmund showed there is little sign of that away run coming to an end but Rodgers is not minded to change their approach.
"We went in high in confidence," he said. "The team's been playing ever so well. So we felt we were in a really good place. But I think we needed to start the game much better than we did.
"I think we may have got spooked a little bit early on. We get the equaliser and very, very quickly we're then 2-1 behind. They get a foothold in the game, start to move it well and we start to chase it a little bit.
"When we analyse the game, there were certain issues, positioning, that we would have to be better in.
"We got punished for passes and loose bits of play. It was absolutely ruthless in the finishing. It was actually incredible to see.
"At times our positioning was a little bit too open and you've just got to really tighten the game or else they play through you, and that's what they did.
"Once they're in then that speed and power that they have at the very highest level, then you see where it takes them."
When Celtic were drawn against Slovan Bratislava, RB Leipzig, Club Brugge and Young Boys at home, plus Borussia Dortmund, Atalanta, Dinamo Zagreb and Aston Villa away, Rodgers said the draw was "absolutely brilliant" but admitted no game will be easy.
Since 2001/02 Celtic have progressed to the knockouts just three times.
However, this new-look format will see the top eight sides in the league qualify automatically for the knockout stages, while those finishing in ninth to 24th place will compete in a two-legged play-off to secure a place in the last 16 of the competition. Teams ranked 25-36 are eliminated from all competitions.
Sky Sports' Kris Boyd believes the Hoops can still progress: "With the home games they have left, they will back themselves to pick up more points.
"At Celtic Park, Celtic will cause teams problems but their performance away from home is worrying. They capitulate once they concede a couple of goals and it is not the first time we have seen this from a Brendan Rodgers team. It is something that needs sorted.
"It was always going to be a tough game in Dortmund but with this new format, Celtic still have a good chance of progressing in this competition."
Celtic will need to take some lessons from Dortmund into their next two European games. Rodgers' side face Europa League winners Atalanta in Bergamo on October 23 before hosting another German side from the top pot of seeds, RB Leipzig.
However, Club Brugge come to town after that and there's a trip to Dinamo Zagreb too, before ending the league phase at home to Young Boys and away to Aston Villa in January.
Mixing with Europe's elite has often rekindled special tales of the past for Celtic fans - so could this yet be the season that creates new memories under Rodgers?
May 25, 1967 will always be one of the most important days in the club's history as they became the first British side to win the European Cup. A team made up of players who all lived within a 30-mile radius of Celtic Park would be crowned the Lisbon Lions after their win over Inter Milan in Portugal.
Some special nights have followed since, including wins over Barcelona and Manchester United at Celtic Park, plus reigning champions at the time - AC Milan - in 2007.
The win over Slovan Bratislava was another special one to add to the list. However, many more memorable results will be required to prove Celtic belong at this level.
To finish in the top 24, which guarantees you a play-off spot at least, Opta believes 10 points - so three wins and a draw, or other combinations - will almost certainly guarantee you a place in that round.
It means whichever teams win in the opening round of Champions League fixtures need just seven points from the remaining seven games to guarantee themselves a play-off spot.
Nine points - so three wins from eight games, or other combinations - could be enough to finish 24th, with that points tally being enough in 69 per cent of the simulations.
But just eight points - so two wins and two draws, or other combinations - runs the risk of elimination, with that points tally being sufficient in just 16 per cent of the simulations.
So teams will be targeting at least three wins from eight to give them the best possible chance of reaching the Champions League knockout rounds.
The 2024/25 UEFA Champions League season will take place in Munich at the Allianz Arena on May 31, 2025.
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