Manager Derek McInnes believes a refereeing error cost Aberdeen in their 2-0 defeat by St Johnstone on Saturday.
Referee Alan Muir adjudged Dons midfielder Ryan Jack to have passed the ball back to goalkeeper Joe Lewis, who picked it up.
Danny Swanson opened the scoring from the resulting indirect free-kick, and Craig Thomson sealed the win late on.
"It's a poor decision from the referee to declare that a pass-back and they've taken full advantage," McInnes said.
"The first goal is always really important against St Johnstone.
"We probably didn't do enough to get ourselves in front, but we certainly didn't look like losing it and I think the referee has a part to play in the first goal.
'We've got the second-best team, but the worst pitch'
"Our set-up in how we dealt with the free-kick is up for question, but I don't think it was a blatant pass back.
"Once we go behind we throw bodies forward and we get done on a counter-attack, which can happen."
St Johnstone are just the third team to leave Pittodrie with three points in this season's Scottish Premiership, after champions Celtic and third-placed Rangers both recorded league wins in Aberdeen.
Despite the defeat, the Dons remain nine points clear of the Ibrox side in second spot with four games remaining, and are 23 goals better off than Pedro Caixinha's men.
As well as the officiating, McInnes also took aim at the Pittodrie pitch.
"It was a dour game and while we may have the second-best team in the country, we have the worst pitch," the Dons boss said.
"It's awful, bobbly and dry and you saw people slipping on it. It's just a poor surface, which didn't help us or St Johnstone.
"I can't be too hard on the players. They put a lot into it but it's a reminder that we have tough games post-split and we've got to make sure our level of performance is better than it was today.
"We're used to winning games here and I thought the referee helped St Johnstone get the first goal, but they countered on us a couple of times after that and got the second goal."
St Johnstone manager Tommy Wright agreed with his counterpart regarding the pitch, but felt his side dealt with it well enough to merit the win.
"It was windy and blustery and the pitch is a bit uneven, so it wasn't a game of beauty," he told BBC Scotland. "But the result is the important thing for us at this stage of the season.
"There were moments of quality from us in the lead up to the back-pass being given [for Danny Swanson's free-kick goal] and the goal from the counter attack and, on that basis, we deserved the win.
"We'll play a lot better with the ball, but one thing we do when we're not playing particularly well is grind it out.
"It's up to the opposition to break you down and I don't think Alan Mannus has had a save to make all game."