"A couple of hundred disgruntled Hoops fans gathered at the front doors of Celtic Park following the defeat to vent their anger at the players and the club's board of directors for a perceived lack of investment in the playing squad.
The defeat means Celtic, who had been looking to qualify for the group stage for the third year running, have lost out on a potential ?20million cash boost from the competition and heaps pressure on Deila early in his Celtic career.
However, the Norwegian said he expected to add more players to his squad before the end of the transfer window. "I really understand the fans' anger, " he said. "The only thing I can do is assure them that we are going to work really hard every day now so that next year we can hopefully stand in the same position next year with a whole other feeling than we have right now.
