St Mirren are not giving themselves "the chance to win games" because they are conceding bad goals, says manager Alan Stubbs.
The Paisley side were hammered 4-0 by Aberdeen in Saturday's Scottish League Cup last-16 tie and were fortunate not to suffer an even heavier defeat.
Stubbs said some of his players were "not taking responsibility".
"We need to cut out basic mistakes that we're making right now," the former Hibernian boss told BBC Scotland.
"We've just played a team that's considerably stronger than us. They've been the second-best team in the country for the last four-five years.
"But that doesn't meant they can play through you at will. The one thing that I want, first and foremost, is 100% effort."
Experienced goalkeeper Craig Samson's slack pass allowed Aberdeen to score a third goal in 10 first-half minutes, but Stubbs would not criticise his number one.
"Craig made other saves that stopped Aberdeen from scoring," he said. "He didn't feel sorry for himself and responded to it. I'm not too sure whether some others can say that."