Dias has only been at the club for four months following his £61 million move from Benfica, but in helping City to the Premier League's best defensive record has cemented his place as one of Guardiola's key players.
"Every step he does, at home, on or off the pitch, eating, sleeping, recovering time, preparation time, everything is to be perfect during this 95-minute football game," Guardiola told a news conference on Tuesday. "It depends on him to maintain and hopefully we can help him to grow. We are more than satisfied.
"He's not just a player who plays good, he's a player who makes the other guys play good too. It's 90 minutes talking, 90 minutes communicating, 90 minutes saying what they have to do in every single action. When that happens, it's difficult for me and undroppable."
Dias, 23, has formed a formidable partnership at the back with John Stones, who looked to be on his way out at the Etihad Stadium in the summer.
"What I want from my players -- all of them, not just John -- is to be happy and he struggled to be happy here, especially with injuries, some personal problems, for many reasons, a lack of minutes," said Guardiola, who takes his team to play Burnley on Wednesday.
"I didn't see him like he is right now. In the past he was not like he is now, with the stability, the mentality, happiness, commitment focusing and everything.
"He overcame this situation himself. He could have fallen down and go even more down, but it was completely the opposite. He said 'no, I'm here, I know how good I am.' He didn't need my confidence, he didn't need the words.
"Players who need confidence to play, it's a big mistake, he cannot be here. John overcame this situation himself. That's why he deserves all my respect and he deserves a big compliment."