It was a Tuesday night to forget for Celtic in the Champions League after being humbled by Borussia Dortmund. Nuri Sahin’s side beat the Bhoys by a massive 7-1 margin, leaving Brendan Rodgers’ outfit bruised and embarrassed after projecting so much hope in the build-up. Preventable individual errors contributed to the heavy defeat. Sloppy passing and poor positioning allowed Dortmund to rip through the Scottish champions repeatedly. It was difficult for supporters, players, and staff to take. After the match, captain Callum McGregor’s disappointment was clear. He didn’t shy away from Celtic’s …