Dias brought the composure, leadership and stability that had been lacking since Vincent Kompany left and his partnership with the reborn John Stones established City as the league's most miserly team.
Even so, when Tottenham beat City on 21 November to go top of a seemingly unpredictable division, City were 11th and eight points off the pace, and it looked as though this might not be their year again.
At Anfield in February, where they had not won in the league since 2003, City bullied and dominated the defending champions, with Phil Foden brilliant in a crushing 4-1 victory.
Stones and Dias' partnership at the back was key, conceding just three goals in the 15 games after that Spurs defeat, while Ilkay Gundogan has been the star at the opposite end of the pitch, his 12 goals so far leading City's goalscorers.
"I am so proud and so happy with what we have achieved," he said. "The Premier League is the hardest league in world football - every single match is tough. To win it again means the world to me and the rest of the squad.
"Winning the Premier League is the ultimate fulfilment of our ambitions. It's what we all dreamed of as young players, so to do it is a wonderful feeling.
"We will enjoy this moment and we hope the fans do too. Rest assured we will continue to do everything we can to bring the Champions League home this season."
"They've been relentless in all competitions and have been an absolute pleasure to watch. They have shown attacking flair but that brilliant back four too. To be within touching distance of four trophies has been just fantastic.