Dundee United manager Peter Houston turned his ire on the officials and excused his players of blame for the 2-1 defeat by Aberdeen.
Houston thought his side should have had a penalty and ought to have had a throw in the lead-up to the Dons' equalising goal at Tannadice.
"The assistant did not get involved at the penalty but certainly got involved in the equaliser," he said.
"I have to question his capability to perform at this level."
United took an early lead through Jon Daly, but their claims for a penalty were rejected when Andrew Considine challenged Johnny Russell.
"It was a glaring penalty," said Scotland assistant manager Houston, who claimed that Aberdeen's captain agreed with his opinion.
"It was a penalty all day long as far as I am concerned.
"He was taken out. He was wiped out and Ricky Foster admitted to our players it was a stonewall penalty - and it would have been a red card as well as it was on the six-yard line."
Aberdeen drew level when Kari Arnason's throw-in was flicked on by Rory McArdle for Mohamed Chalali to head into the net.
"Paul Dixon clears it up the park, it hits the Aberdeen player, it goes out for the throw-in and they score from the throw-in," said Houston.
"No excuses for the defending at the throw-in, but we need people who are capable of doing their jobs right.
"And, as far as I'm concerned, the assistant linesman on this side, I have to question his capability to perform at this level. Maybe it's too much for him."
Arnason scored the winner from distance and Houston thought goalkeeper Dusan Pernis could have prevented the goal.
"He says it was moving all over the place, but I still think he could have done better," said Houston.
"He rockets it from 45 yards and you think you have time to do better and it hits the underside of the bar and goes in."
Overall, Houston thought his side should have won the game.
"If we go 2-0 up, we go on to win the game," he added.
"Johnny Russell's had a great chance, Scotty Robertson's had a great chance that the goalkeeper's made two great saves from.
"We totally dominated the first half and I just can't believe we've got nothing from the game.
"I feel very hard done by and I'm really disappointed at the officials.
"But, as far as the players are concerned, I thought we were great at times."