Brendan Rodgers claimed 10-man Celtic's 2-0 defeat at Hearts was "decided by the officials" as he lamented an early red card for Yang Hyun-jun and the award of the penalty that allowed the hosts to take the lead.
The Hoops arrived at Tynecastle knowing a victory would have taken them back to the top of the cinch Premiership after title rivals Rangers suffered a shock home loss to Motherwell the previous day.
Celtic's chances were undermined in a dramatic opening quarter of an hour when Cork's Adam Idah saw a penalty saved by Hearts goalkeeper Zander Clark a few minutes before Yang was sent off for catching Alex Cochrane in the face with a high boot.
The South Korean was initially yellow-carded before match referee Don Robertson upgraded it to a red after being advised by VAR John Beaton to review the incident on the pitchside monitor.
Rodgers was further riled when Hearts were awarded a penalty in the 40th minute after a headed clearance from Liam Scales landed on Tomoki Iwata's arm as he rose to try and head it out of the box. Jorge Grant scored the spot-kick and Lawrence Shankland netted the hosts' second goal in the 56th minute.
"My feeling is that the game was decided by the officials, on the field and outside of the field," said Celtic boss Rodgers.
"You guys (the media) will know me long enough to know that I don't really comment on officials - they make mistakes and whatever else - but today that felt like really really poor officiating.
"The first one is the sending off when there is no force. Show a still image of that and of course you will see a foot up with the head near it, but it's not the reality of the move.
🗣️ "That cost us today, the officiating."
— Sky Sports Scotland (@ScotlandSky) March 3, 2024
🗣️ "You will have to ask John Beaton what he's seeing."
Brendan Rodgers gives his thoughts on Celtic's loss to Hearts and key decisions in the game 🔽 pic.twitter.com/JcPcdONBBl
"Don Robertson actually got it right on the field. It was a high boot, so it's a yellow card - no malice or force.
"For John Beaton to actually look at that in VAR, supposedly under no pressure, and say that was a sending off, I find that incredible.
"The second one (Hearts' penalty) is worse. If you have a penalty go against you for that then there will be penalties every single weekend and midweek.
"I don't know what he (Iwata) is supposed to do. Tomo is jumping, he got a nudge, he is coming down, the ball falls on to his arm and there is no intention to move.
"Then you get the penalty against and he gets the chance to look at it and see it. That really left us with an uphill task in the game but credit to my players, they kept going, their keeper has made a few good saves.
"But it was a poor day for the officials. I try to respect decisions and give the benefit of the doubt, but when I see that level of incompetence, which is the only word I can use, then that makes me worry for the game.
"In such a tight title race - which it is, and it's fantastic to be involved in - that can make the difference. And that today made the difference for us."
Hearts boss Steven Naismith insisted his team deserved their victory and felt both sides were on the receiving end of "soft" penalty awards.
"It was an entertaining game and one I think we deserved to win," he said.
"There were a lot of action points. Throughout the game at the right times, we played, controlled the game and asked Celtic some questions. I think both penalties are soft.
"Alex puts his foot on the ground and the Celtic forward is the one that kicks him. Ours is this handball rule that nobody is happy with. And I think the red card is a red card."
Asked if the two debatable penalties effectively cancelled each other out in terms of controversy, Naismith said: "We saved their penalty and scored the one we got.
"Both teams can feel that they were soft but overall we deserved our win comfortably. It was two and it could have been more."