Zinchenko, who joined City from Ufa in 2016, appeared on the verge of joining Wolverhampton Wanderers at the beginning of the season but stayed at the Etihad Stadium and has made 16 appearances in all competitions.
The 22-year-old played the full 120 minutes as City won the Carabao Cup final on penalties against Chelsea on Sunday.
Guardiola has been impressed by Zinchenko's attitude in training and his response to limited first-team opportunities in the Premier League.
"Incredible is the only thing I can say," said Guardiola. "Oleks has showed me again what I thought before; the importance and the value of being a good guy, a good lad.
"And the fact he's a guy who was making a transfer - at the beginning of the season was close to going there [to Wolves]...there was six, seven or eight fixtures he didn't play one minute.
"But I never saw him in the period we were together with one bad face, one bad training session. The day after the games is always difficult for the guys who didn't play [in their] training session and most of the players sometimes want to show me how disappointed they are. Then maybe before the game they are nice again in front of the manager and their team-mates.
"This guy was the complete opposite. That is the reason he always plays good. He showed me again the mood, the behaviour, being positive, smiling and alert. When this happens, you will always play good.
"That's why I'm delighted. He deserves all my respect and I think he's going to make a long career. I don't know if that will be here, hopefully, or another place, but with this behaviour he will be happy doing his job.
"I can only say thank you. More than the way he plays, it's his approach. Everybody can learn from Oleks. Everybody."