Dundee United manager Gordon Chisholm said he was in "a state of shock and disbelief" after exiting the Uefa Cup.
"It's a major disappointment because we were in total control at 2-0," Chisholm told BBC Sport.
"The dressing room is silent. The players realise what a strong position we had and they are all gutted.
"We enjoyed the experience of being involved in Europe and it was something we wanted to continue. I'm in a state of shock and disbelief."
United appeared to be cruising at 2-0 until Stuart Duff conceded a penalty that was converted in the 74th minute.
"I didn't see the incident but a silly error has given them a massive lift and brought them back into it.
"For the second goal we tried to squeeze up and got caught with a quick breakaway.
"It's a huge let down for the fans, who were magnificent.
"I warned the players about complacency at half time and we started the second half at a good tempo.
"I don't think we took our foot off the gas but we tired and we weren't as positive."