Aberdeen manager Barry Robson felt his team wasted an opportunity to defeat HJK Helsinki and register their first win in the Europa Conference League.
The Reds dominated the match against their Finnish opponents but they failed to make their possession count as the teams played out a 1-1 draw at Pittodrie.
Robson said: “I am frustrated because we deserved to win the game.
“I am disappointed with the goal we lost because it was their only shot at goal but that was testament to the way we defended and pressed.”
“The frustration comes from having 17 shots and only scoring once. We needed to be a bit more clinical and had we been done so, I think we could have won that game by three of four.”
“That was a good performance.”
“That is five games in a row where we have really performed and we have scored 11 goals but the sucker punch is Helsinki scoring with their one real chance.”
Robson was unimpressed by the standard of refereeing after Duk suffered a nasty head injury following an apparent elbow from Georgios Kanellopoulous in the first half.
Polish referee Daniel Stefanski was not asked by the VAR official to review the incident, which resulted in the Cape Verde international requiring treatment.
Robson said: “I was massively surprised he was not asked to look at it.
“I need to be careful on what I comment on but I think we all know the level of player and the level of game has to be officiated at the correct standard.
“I did not think the standard was correct tonight.
“There were a lot of things that happened out on the pitch that were not right for me.”