The Argentine defender did little to endear himself to the Etihad faithful after conceding costly penalties in UEFA Champions League and FA Cup clashes with Barcelona and Wigan Athletic respectively.
He has, however, offered the perfect response to those mistakes by forming a watertight centre-half partnership with City skipper Vincent Kompany.
The pair had collected five successive clean sheets prior to Saturday's 1-1 draw at Arsenal, with Demichelis now putting his vast experience and undoubted ability to good use.
He said in the Manchester Evening News: "My confidence is high and I feel I am in really good form and am happy to help the team.
"It's true that I conceded penalties in two different competitions, and it's true they were punctual mistakes, but I am not in bad shape and am full of confidence.
"I could have been worried, for example, that Olivier Giroud might win all the high balls, but he didn't, and I could have been late into challenges, but I wasn't.
"I felt I played well at Arsenal and my form is high - and the positive messages are good."
Demichelis arrived at City late in the summer transfer window and suffered ankle ligament damage in his first training session which kept him sidelined for two months.
He has worked hard to recover form and fitness and believes he is now getting to grips with life in England.
The 33-year-old added: "Saturday's match was an example of what the Premier League is about. We played with a high tempo, plenty of intensity and pace, but so did Arsenal.
"It was a difficult match, and that is why the league is one of the best in the world. That is why we need to work so hard in the eight matches to the end of the season.
"It's not easy, not only because there are a lot of teams challenging for the Premier League, but also because there are a lot of teams fighting relegation, or trying to qualify for the Champions League or Europa League.
"I want to stress that it won't be easy from now until the end of the season, but we have to keep working hard and hopefully will win the title."