Celtic retained the Scottish Premiership title on Sunday with a hard-fought 2-0 victory away to 10-man Hearts.
Sunday's victory moved Celtic to 95 points after 34 games, enough to seal the club's 53rd in the Scottish top-flight and their second in two years under Australian head coach Ange Postecoglou.
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Celtic, who already lifted the Scottish League Cup in February, can complete a fifth treble in seven seasons when they face second-tier Inverness Caledonian Thistle in the Scottish Cup final on June 3.
"Super proud, It feels like it's been a long year. This group of players and staff have been outstanding, maintaining an almost impossible standard week-in, week-out," Postecoglou told Sky Sports.
"It's a daily thing. We won it last year, there's always a danger that maybe guys will get ahead of themselves, but from the first moment after we came back from pre-season we set our target.
"Last year's success we put to bed straight to bed and we really raised our standards this year."
The scores were level on Saturday for much of the match, but Hearts defender Alex Cochrane was handed a red card on a the stroke of half-time in a controversial VAR review before Celtic eventually took full advantage.
SPFL top scorer Kyogo Furuhashi gave Celtic the lead on 67 minutes, and Oh Hyeon-gyu added the side's second on 80 minutes to seal three points, as well as the title.
"I did have a moment after that first game [against Hearts in July 2021] we had a mountain to climb, but I really had belief I could do something here and build a team these fans deserve," Postecoglou added.
"We have a great opportunity to make this season really special. The whole football club have embraced me from day one and I'm really grateful to give something back.
"You get emotional because you understand what's gone into it."