Celtic’s defeat to Borussia Dortmund is still a sore one for the fans to digest. Whilst the win over Slovan Bratislava at Celtic Park gave the supporters reason to be optimistic for the upcoming Champions League campaign, the defeat to the Bundesliga club delivered a healthy dose of reality to the Hoops fans. Celtic got battered at Dortmund in a bruising 7-1 defeat and it has left some fans looking forward to the Atalanta fixture with an air of trepidation. The current Europa League holders have enjoyed a draw with Arsenal and a win over Shakhtar Donetsk in their two opening league games and w…