Glasgow: Brendan Rodgers said Celtic had capped a "fantastic season" after Adam Idah's 90th-minute winner beat Glasgow rivals Rangers 1-0 yesterday to lift the Scottish Cup and complete a double.
A scrappy game was decided by an error as Jack Butland fumbled Paulo Bernardo's effort and Idah pounced for his ninth goal of a loan spell from Norwich.
The Irish international's goals since joining in January also helped Celtic usurp Rangers in the final months of the campaign to win the Scottish Premiership for a third consecutive season.
"It's a game you don't need to be perfect, you just need to win and we did that by the end. We found an energy and a will and desire to keep pushing," said Rodgers.
"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."
Rangers thought they had taken the lead earlier in the second half when Abdallah Sima turned home a corner at the far post.
But after a VAR review, Celtic goalkeeper Joe Hart was handed a reprieve in the final match of his career as the former England international had been pushed by Nico Raskin.
"That we didn't score and Celtic scored, I think that was the only difference," said Rangers boss Philippe Clement, who is yet to win an Old Firm derby in four attempts.
"Everybody saw it was really close. We're going to need a rebuild... We are going to build a new team."
Celtic were far from their best but maintained an unbeaten record in five meetings against Rangers this season, which has also secured them direct qualification for next season's Champions League by winning the Scottish Premiership.
Idah started on the bench, but came on to have the telling impact after a rare mistake from Butland this season.
"I said I'd come here to try and score as many goals as I could, I didn't think I'd score a goal like this in front of all these fans. It's an amazing feeling," said Idah.
"It's hard to put into words. Anyone here can see what it means to the fans, to the players. I've always supported Celtic, it's amazing!"
Victory also continued Rodgers' remarkable Scottish Cup record.
The former Liverpool boss has never lost a Scottish Cup tie in 17 matches and takes his trophy haul as a Celtic boss to nine in three-and-a-half seasons.
Celtic's win also has historical significance as they move level with Rangers' total of 118 trophies.
The head-to-head between the clubs is also now level after 441 meetings with 169 wins each and 103 draws.