City's unwanted three-match winless run came to an end on Sunday when they beat local rivals United thanks to Sergio Aguero's second-half strike.
Confidence levels had dropped following the bad run of form, which had seen the club draw with CSKA Moscow and suffer defeats to West Ham and Newcastle.
But Zabaleta thinks City's self-belief is now strong following their morale-boosting victory at the Etihad Stadium on Sunday.
"It was a great victory because we needed those three points to get confidence back and hopefully that can continue," the City right-back said.
"It was a massive win for us
It's one of those games that everyone enjoys winning.
"The derby is always special and I'm glad our fans can enjoy another win."
Even though they won, City were unhappy to have scored just once against a United team that was down to 10 men for the majority of the game because of Chris Smalling's silly dismissal.
Pellegrini's team were far more prolific against United last season, when they recorded a 7-1 aggregate win over their rivals.
United were not the only team to get a pasting off City last term.
City beat Arsenal 6-3, scored five against the same CSKA team they drew with two weeks ago, and they put 11 goals past Tottenham over the course of two games last year.
Now Zabaleta hopes City will start producing similar results to help them in their quest to catch leaders Chelsea.
"We had to get back to our best form to be the team that we used to be - sharp, clinical and aggressive," the Argentinian said.
"This is the team we want to see week-in, week-out.
"It has been a tough start to the season for the big players who came in late (after the World Cup) and we didn't have a good pre-season.
"There is still a long way to go and we are still confident because we are only six points behind Chelsea."
City will be hoping for an upturn in form in Europe too - starting with the visit of CSKA Moscow on Wednesday.
The Blues drew 2-2 with the Russians a fortnight ago, leaving them with just two points from their opening three games.
The Champions League appears to have not gripped the imagination of City fans - the club are offering two tickets for the price of one for Wednesday's game in a bid to fill the stadium.
But Zabaleta is hungry for success in the competition.
"Now we need to focus on the Champions League because there is a crucial game coming up," Zabaleta said.
"We are desperate to qualify for the next round so we know how important that game is."
City have been boosted by the news that Frank Lampard could be fit for the game.
"I'm not far off selection," the midfielder told City's website on Sunday.
"Fingers crossed, if all goes well over the next couple of days, I'll be back in contention.
"I had a small injury in my thigh - an old injury I'd disturbed slightly."
Lampard has enjoyed an impressive start to life at the Etihad Stadium.
The former England midfielder has scored four times in six matches since joining in August.
Lampard was reluctant to say whether he would like to extend his stay beyond January, when he is due to join up with New York City FC, but he admitted he is enjoying life in the north west.
"All I can say is how much I'm enjoying it at City," said Lampard, who was in the crowd with his family to watch the derby on Sunday.
"I'm contracted here until the end of December and my future will be at New York City at some stage.
"All I can do now is go week by week and play as well as I can when I am playing to bring a good contribution."
Source : PA
Source: PA