City found it tough to overcome Villa but four goals in the last half hour saw them claim a vital victory, with Edin Dzeko netting a brace before Stevan Jovetic and Yaya Toure added two more goals in the final minutes.
The result leaves City two points clear of Liverpool heading into the final weekend of the season while boasting a significantly better goal difference to their only remaining rivals.
Zabaleta is delighted to be closing in on the title but recalls the last-day drama that won them the title in 2012 on goal difference from Manchester United - and is taking nothing for granted.
He told Sky Sports 1: "I think it's a massive step forward but we know that there's still one game to play and we had the experience two years ago on the last day of the season against QPR, and sometimes you don't know.
"We know (City's final day opponents) West Ham are safe but they have very good players, they play really well on the counter-attack, they can score on set-pieces, so it's going to be very very tough, like tonight, so we can't relax."
He added: "It was a very difficult game (tonight). It was a very solid performance, nothing is done yet, we know that there's still one game to play but it was very important to win tonight.
"We have a great chance so hopefully on Sunday we can celebrate the title."