Philippe Clement cut a furious figure at the end of the Scottish Cup final after he felt Rangers were hard done by with a few key decisions going against them.
There was nothing to separate the two Old Firm rivals after a cagey first half display with neither goalkeeper being truly challenged.
But the match sparked into life after the break as both sides pushed for an opener.
Rangers had the ball in the back of the net after a teasing corner from James Tavernier was turned in by Abdallah Sima.
However, referee Nick Walsh was advised to go to the monitor before the goal was disallowed for a shove from Nicolas Raskin on Joe Hart.
Philippe Clement was not happy with the referee's performance
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Rangers were unable to bounce back from that setback with a mistake from Jack Butland leading to Adam Idah scoring the match-winner late on.
Clement cut a dejected figure as he led his side up the steps to collect their runner-up medals.
But the Belgian coach was unable to let go of a few decisions he felt the referee got wrong.
"By far our best Old Firm this season," he told Rangers TV.
"The better team, getting six shots on goal, they got two shots on goal.
"You feel you are so close to winning, then the disallowed goal - really, really big decision from the referee.
"The better team, getting six shots on goal, they got two shots on goal.
"You feel you are so close to winning, then the disallowed goal - really, really big decision from the referee.
"If you compare with other decisions like the push on Dujon Sterling in the first half, which was 10 times more than that, but no foul.
"So disappointed about that. But I'm most disappointed for the fans, we wanted to give them that."
Rangers scored first but the goal was disallowed
REUTERS
The result saw Brendan Rodgers secure the Scottish Cup and league double in his first season back as Celtic manager.
Rodgers accepted that it was far from a vintage performance from his team, but was delighted that they were still able to get the job done.
"Obviously for the spectators, it was very tense. It's a game you don't need to be perfect, you just need to win and we did that by the end," he said.
"We found an energy and a will and desire to keep pushing. Thankfully, we got a winner.
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Brendan Rodgers was delighted with his team's display
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"I said to the players, when you're preparing for a final it's not about what you done the week before it's about the other 51 weeks. All the players, their mentality and professionalism has been unbelievable.
"It's been a fantastic season, to win a double. The problem is that when you win trophies, it becomes an expectation.
"That's not a problem. You can't take away what the Scottish Cup means for this club and our supporters.
"Rangers came in with a big motivation. We knew there would be challenges in the game. It's all about the defining moments and we were able to get the winning goal because of that."