DORTMUND, Germany (Reuters) - The 'acid test' turned sour for Celtic manager Brendan Rodgers after Borussia Dortmund dealt his side a 7-1 Champions League thrashing on Tuesday.
After beating Slovan Bratislava 5-1 in their European opener and on a 17-match winning run in all competitions, including nine this season, Celtic had confidence they were now a force to be reckoned with.
The dream lasted only a matter of minutes. After both teams' fans had sung their shared anthem 'You'll Never Walk Alone', Celtic were very much on their own as last season's beaten finalists ran wild with five goals before the break.
Among the home highlights, player of the match Karim Adeyemi scored a first-half hat-trick.
For the third time in his managerial career, after 7-0 and 7-1 drubbings by Barcelona and Paris St Germain respectively in 2016 and 2017, Rodgers saw his side ship seven goals in the Champions League.
"I don't think I've been involved in a game where every mistake we made got punished," a disappointed Rodgers, who had spoken before the match of it being an 'acid test', told TNT Sports television.
"It was a tough watch, to be honest. We weren't at our best. They showed why they are a top, top team. We didn't make the start we wanted.
"We went in high in confidence. We felt we were in a really good place. We had to start much better than we did, as we gave away really cheap goals. And we got punished for loose bits of play and passes.
"They were ruthless in their finishing. It was incredible to see," he added.
The former Liverpool and Leicester City manager had said before the game that Celtic were playing "for the dreams of the supporters".
He had said the Scottish champions had become a really difficult team to play against and he was not looking for perfection.
"My job is to go away and inspire the players again. We need to learn from it or we will get punished at this level," he declared aftwrwards.
(Reporting by Alan Baldwin in London, editing by Ken Ferris)