The Champions League has a habit of inflicting these inglorious episodes on Celtic. It is difficult to shake the notion that this big fish will always drown when removed from its small domestic pond. Borussia Dortmund toyed with their visitors in a match that was over as a contest long before the half-time whistle blew. The Germans have won two out of two in this new format. They will have aspirations of equalling last season’s memorable tournament run, albeit with far sterner tests than this ahead. This was akin to a Grand Master playing an orangutan at chess. Men against Bhoys. Suddenly there is pressure on Celtic’s upcoming trip to Atalanta. The paucity of their showing here undermined what had been a much-quoted sense that Celtic were better equipped for the Champions League than at any point in recent history. Theirs was a fragile, error-strewn display. Brendan Rodgers has now been in charge of three different Celtic teams that have lost seven goals in a single Champions League match. There is a six and a five in the Rodgers record as well. “It was a tough watch,” Rodgers admitted. “Nights like that are tough but they can happen at this level. You have to learn from it and move on. We came in high on confidence but we needed to start the game much better than we did.” European football’s governing body was in profit before a ball was kicked. A fine will inevitably be issued after the teams emerged to giant banners in the Yellow Wall, branding Uefa as “mafia.” Underneath read the slogan: “You don’t care about the sport, all you care about is money.” Pyrotechnics from the Celtic support will also trigger a sanction. A madcap opening soon took attention away from what had transpired in the stands. Celtic did the very thing they were so anxious to avoid by handing impetus to Dortmund, only to claw their way back into proceedings and concede a second goal that was as defensively soft as the hosts’ first. There was a touch of fortune attached to Jamie Gittens winning a penalty from the despairing Kasper Schmeichel. Gittens won the break of the ball from Celtic’s captain Callum McGregor when breaking from midfield. Still, the Dortmund man should have been halted long before Schmeichel had to upend him. Emre Can’s reacquaintance with Rodgers, once his manager at Liverpool, was a positive one for the midfielder as he sent Schmeichel the wrong way from 12 yards. Celtic’s response was immediate. A wonderful Arne Engels cross from the right flank left the Dortmund defence flat-footed. Daizen Maeda stole in to score - via his midriff – and trigger wild scenes among the visiting contingent. That joy proved short lived. A third goal in four minutes arrived from Karim Adeyemi, who beat Auston Trusty for pace before lashing a shot beyond Schmeichel with the assistance of a deflection from the same defender. During the first half, Dortmund cut Celtic open time and again with astonishing ease. In respect of the Scottish champions against the elite of Europe, this was eerily familiar. Adeyemi, central to everything that was good about Dortmund, notched his team’s third. At this point, Celtic were flailing on the ropes. Again, there was generosity attached; the kind that will typically go unpunished in Scotland. Celtic only half cleared a corner, with Adeyemi picking up the loose ball. Schmeichel clearly was not expecting a shot, which flew past him at the near post from a tight angle. Celtic had conceded four goals all season before this fixture. Another penalty ensured the same tally inside 40 minutes. Engels carelessly kicked the foot of Adeyemi, leaving the referee no option but to intervene. Adeyemi graciously passed on the opportunity for a hat-trick – he would have banked on achieving it anyway – with Serhou Guirassy this time doing the necessary. It was five by the interval. Adeyemi did indeed get the treble his excellence deserved, with a low drive after Maeda coughed up possession. Dortmund had been ruthless. Celtic’s goal difference from the 5-1 trouncing of Slovan Bratislava had been cancelled out in one dizzying half. Rodgers believed his players had been “spooked” during that opening period. A disconsolate Adeyemi limped off, three minutes after the restart. This felt the biggest boost of Celtic’s night. Schmeichel turned Julien Duranville’s shot round a post as Dortmund pursued their half dozen. There was, however, a notable drop in intensity from Nuri Sahin’s team. Their work was essentially done. Number six did come. Alistair Johnston passed the ball straight to the opposition, which led to Guirassy facing down Liam Scales. Celtic’s centre-back was comfortably beaten before Guirassy wrong-footed Schmeichel. Further comedic defending brought the Dortmund seventh. Trusty, enduring a torrid time, gave the ball away. Felix Nmecha returned it with interest. There endeth Celtic’s latest horror show.